Hope it helps!
I stripped a TPS screw when I was installing a new throttle body, so I know how much of a pain that can be. I ran with only 1 screw for a bit, but I ended up getting a new one from PepBoys or Autozone (can't remember which, either Duralast or ACDelco, something like that) and it was about $25. It came with both screws and a new gasket. If its cheaper online or just a brand you trust more go for it, as it should come complete with the stuff mine had.
As for the stripped screw, I don't remember how I finally got mine out, but most auto or hardware stores should have relatively cheap (but functioning) stripped screw/bolt removal kits. I haven't tried these myself but I've heard they're OK.
And finally, if you're driving w/o the TPS now, it might end up confusing the car a little, but I'm not sure it will do anything REALLY bad. Your Air/Fuel ratio might get a little screwy (which can throw a few to a ton of trouble codes at you), but I'm not sure. I accidentally forgot to reconnect the TPS before the new TB test-drive, but there was/is no lasting damage.