OS: Windows XP SP2 / Windows Vista / Windows 7 (32 or 64-bit)
CPU: Intel E8400 Core 2 Duo or AMD Athlon X2 5600+
Memory: 2GB RAM+
Video: NVIDIA GeForce 8800 (768MB of video memory) / ATI Radeon HD 3850+
Sound: DirectX 9.0c Compatible Soundcard
DirectX: Version 9.0c or Higher
HDD: 10GB Free Disk Space
Network: Internet Broadband Connection Required
Disc: 6X DVD-ROM
Yeah, it seems to me something is wrong, you should be running pretty good at medium settings with that rig. Check your GPU temps and CPU performance while running STO
There is nothing wrong with purchasing a new video card now. You can always put it in a new build later .
But... there could be one issue, 8800GS cards were built as PCIe and AGP slotted cards
If it is an AGP slot card I would not recommend an upgrade. You have to pay to much of a premium for a decent AGP card these days and you are not going to get a much faster card than the one you presently have.