The cross section of the front part of the frame has rusted to the point that the right wheel is rubbing. what is that part called so that i can locate it?

Year make and model? If you have a front wheel drive? you have a serious frame and mount problem. My guess would be the frame is rusted away. Probably should not be driving this car.

go to a wreckers that handles your make of vehicle and buy that section complete ( rust free unit)
drill out the spot welds where the rust unit is attached to the body sub frame
do the same for the new section
position the new section in place against the sub frame and you have 2 options her
either weld the parts back together ( best get a qualified welder to do this)
or drill holes and use grade 8 bolts to bolt the sections together
remember that it is an integral part of the sub-frame so it has to be done properly for safety

Under the car behind the right front tire there is a pinch of welded sheet metal that is along the frame, Place the jack there just six inches from the point in which it starts

If this is an alignment rod Bar that you are talking off that goes back to the lower arm and the rust is in that attachment point where it is mounted to the frame Then it can be repaired with a new section being welded it but you will need an accredited welder / panel beater to do the job . If it is rusted through the frame then have the whole frame checked because rust is not always visible until the paint is disturbed. This part is vital to the steering stability and if not done properly will result in serious injury to the driver and others.

Well, yes and no!
If you are referring to what I will be calling the "A" frame, which holds the strut and the wheel and ball joint, etc., that part is replaceable.
If, however, you are speaking of the part that the "A: frame bolts to, here is the only way I know to fix it cheap.
I had a '97 Sable and the front end was smashed. I found a salvage yard, actually a crush yard, that sold me the WHOLE front end of the car for $ 125. You can cut whatever you want off of this and weld it to whatever you need fixed.
A crush yard is in the business of crushing cars, so they sell parts and sections of cars a whole lot cheaper that a junk yard.
I am guessing you may live up north where rust from road salt is a problem, and I don't know if cheap car sections are available or not.
I know in Indiana, they strip cars right down to the bare bones before they crush them. Maybe you could fine one like that that you could cut a hunk off of cheaply.
Be blessed.

It should be on the cross member in front of the car,The cross member is the section that is between the two from frames. If you can fellow your steering wheel linkage under the hood down it should lead you to it

Yep, Sounds like you have a bad misalignment that is causing stressing of the suspension. This also may cause another accident or cause injury. Have a body shop give you an estimate to repair the damage. They may tell you what is not right. If the cross member is obviously bent, they may be able to straighten it. If you are confident you can fix it, measure a good one, same model. take pics with your cell phone. Get all the frame mounting points as close to factory as possible using a solid good original point as a reference. Also check the top components are probably bent as well. Harbor Freight sells a hydraulic ram kit that may help. be very careful and should only try this is you are very handy, very safe, and a general fabricator.

How can a 13 year old sub-frame, have rusted out?
You could remove it,media blast it,and cut out rusted sections and weld in new.
You could get a used one from a salvage yard.

unless the vehicle has been in an accident it in not the frame, sounds to me like your wheel well liner is hanging down and rubbing on your tire if this is the case then it will only be a few dollars for some hardware to reattach it you should find what you need in the help section at your local auto parts store

Remember if you do five turns on the right side do five turns on the left side.
First, get both front wheels off the ground (jack the truck up from the frame). Look underneath, at the tortion bar and follow it back to the cross member. Recessed inside that cross member is the adjuster. Turn the bolt clockwise to raise truck. After five turns on both bolts let the truck down and see how much space is between the lower control arm and the rubber stopper. You should see about an inch. The upper control arm should not touch the frame and as well, there should be about an inch of space there too.