Depends on what it needs. If there is a crack or break, it will need to be reinforced and welded. Personally, I don't trust my welding skills all that much, so I'd take it to someone else.
If you're certain there aren't any cracks, then it's just a matter of finding a way to apply (and control!) enough force in the proper direction to bend it back into shape. Chains, heavy timbers, jacks, maybe some big anchors in the floor; that kind of thing.
I'm a little gun-shy, as one of my previous TR3s had one of the A-arm pivots broken loose from the frame before I got it. Even knowing there was a problem, I didn't spot the break, and neither did the alignment shop I took it to. Just sitting, the crack was almost invisible (hard to see that area, plus it was somewhat hidden under the accumulated grease and dirt); but under hard braking it would spread and the car would absolutely insist on turning left, no matter what you did with the steering wheel. Someone pulled out in front of me once and I wound up straddling the median ... scary to think what if there was oncoming traffic and no median.
We had a local frame shop give a presentation to the local TR club a few years back. ISTR the usual price was $250 to pull it to within 1/8" of "perfect". Not sure if that included welding or not, probably not.