Need more fps in quake3 Team Arena

I recently bought ta and my fps drop from 90 to 30 or even 20.Setting quake to low detail did not solve the problem.I run quake in 16 bit-mode.My system is
AMD Athlon 1200 MHz
QDI Kinetiz 7T
GeForce 2 MX
192 MB Ram/133MHz
Please help! :confused

Grab q3 1.27h a small clent side patch for 1.27g