ATI Radeon X1900XT 512 MB  for mac pro first  gen

I am looking for a new graphics card for my first generation mac pro desktop (built 2006)  Currently has ATI Radeon X1900XT 512 MB  installed   Any suggestions on where to find one   
Alternative may be to get a new machine
M Ferro

For me, the best place for any type of upgrade on your Mac Pro 1,1 (mine is a 2.66) is at Other World Computing.
The only video card available from OWC is the ATI Radeon 5770 HD.
Note: The same video card is also available at the online Apple Store.
I'm hoping to get it soon.