It depends on settings. Ram will allow you to run up to ~ 30 bots. CPU might handle it, if you will use lowest settings, and cap framerate at 12 fps (this is not advised, honorbuddy wiki recomend 30fps). You didnt say a word about GPU.
I have no experience wit Nvidia, if I would have to choose cheapest gfx card to run 30 bots, I would pick Radeon 5850, but 5770 might also handle it.
Keep it mind, HB might consume lots of CPU resuroces. I was tweaking settings to get best performance recently, and If you will let hb run wild, it might consume 3x more cpu than wow. You can throttle it with wow fps, but quality of boting will decrease.