Aircommuter kinda hit the nail on the head. not much there to work with. Having said that, any 110 welder is likely not going to be useful. TIG or MIG the key is weld penetration. I've welded with TIG for the most part. when my TIG broke down, I couldn't afford a new TIG so I started using my MIG 220V for everything big. I have a 110 MIG as well but for a frame, thick steel, I always use my 220v. Without weld penetration, you're not likely to get anything that will hold up. and on a suspension part, last thing you want to do is be going down the highway when it gives.
a long extension cord is also not going to help your cause. the voltage drop will not be a good thing for what you are attempting.
the fact you're asking what welder to rent, I'd have serious concerns on getting things done and be safe driving down the road. No offense but something like this, get someone who knows what they are doing before you hurt yourself or others on the road.