Type 3 suspension?
 

I have a 1970 fastback and I want to upgrade and beef up the suspension, what options do I have?

Sway bars, and adjusting the torsion arms front and rear are about it. The beam has splined torsion bars like the rear. So, you can adjust them for different heights and stiffness. You shouldn't need much more than that though...

who sells sway bars for a type 3?

Well, CIP1 has them. Front bar p/n ACC-C10-4048, and rear p/n ACC-C10-4049 $69.95 each... ;)

Cip1? Err I ont know how much I trust the quality of their stuff, Every rubber seal I bought from them about a year ago is full cracked now, Can I realy trust something like a sway bar from them? Isn't their any performance places that sell such parts?

as far as I'm aware no one makes performance parts for the type 3

I had an early squareback years ago, and there were many new cars that didn't ride as good, kinda like a small odd german cadilac.

I think a nice set of adjustable shocks (may require some fabricating to make happen) and a beefy anti-roll bar front and rear, it could be quite a performer.
for anything beyond that see here

The sway bars are made by EMPI (not to good either). Bugpack might have them, but you can't buy directly from them. White Line may have sway bars for T3's. They are out of Austrailia I think, but Aircooled.net carries some of their stuff.