That’s about $640 without monitor, or software, not enough ram, not supported by Apple. So another $300 for monitor. Plus OS. So call it $1000. For another $250 you can get Refurbished iMac 21.5-inch 2.7GHz Quad-Core Intel Core i5. Still not enough ram. Still need external media drive. I think you want to be editing not be a hackintosh hobbiest.
Also you didn't say what NLE you want to use. AVID works on both platforms; Adobe works on both. FCP 7 is EOL. FCP X - the jury is still out. So if you can't afford a Mac get a PC. Setting up a true editing station costs more than your budget. Barebones you can get started. If you have FCP 7, stick it on a used Imac and you'll be fine for a couple of years. Or if you are student get the ed discount on Adobe PP or Avid MC and stick it on a PC.
MacPro4,1 2.66GHz 8 core 12gigs of ram. GPU: Nvidia Geoforce GT120 with Vram 512. OS X 10.6.x; Camcorders: Panasonic AG-HPX170, Sony Z7U, Canon HV30/40, Sony vx2000/PD170; FCP 6 certified; write professionally for a variety of media; teach video production in L.A.