I'm not that good with computer parts either, but I've asked this question before and this is just a transfer of information kinda thing.
Graphic card isn't that important when it comes to botting, the most important parts are the Processor and RAM. For 5 bots 8gb ram would be fine. For processor, you'll get people advocating either i5 or i7. i5 is more than plenty to deal with 5 bots. If you're planning on going the VMware route, it's better to go with i7.
Because the graphic card isn't that important, you can save on the power supply and settle with the highest possible graphic card that the power supply can handle. Example is I had a 550GTX-Ti, which was the most powerful graphic card that I could get that my power supply could handle. A power supply with more wattage beyond that point would cost significantly more (though I can't remember what the wattage was).
Edit: If it's a computer dedicated to botting, then you could probably go for mid-range on all the parts. Also there isn't much difference between a HDD (I'm using a green one no less) or SSD when you're talking 5 bots (based on observation as I have both and tried on both). It does make a difference when you're doing something else on the foreground (my bots lag a tad once I start playing SC2, so I assume the same thing would happen if you were to run any application that would consume a good portion of your PC resources).
