my 1996 850's tail-lights are not very bright is there any one who knows where i can buy some?...or a really good site for aftermarket volvo stuff

There are no aftermarket taillights for Volvo's per say. You can upgrade I believe to the ones that have the clear middle lens, but you may already have them.

http://www.fcpgroton.com
http://www.ipdusa.com
http://www.eurosporttuning.com
http://www.volvomotorsports.com
http://www.vptuning.com

There are some aftermarket Volvo links for you.

Chip Tuning: Upsolute, RICA, IPD, EST, Speed Tuning USA

You find anything yet?

You could tint yours to look different as well. Or you could go custom with some other aftermarket lights which IMO none of them look good at all.