XY Plotter/CNC style interpolation project. Need great deal of help

Thanks so much for all the help so far, guys! I really owe a huge chunk of my master's thesis working (here's hoping it does!) to your volunteering help!

I have gotten the impression that my 6V 1amp radio shack power adapter isn't cutting the mustard.
The motors each (of which there are 2) require 6V and 0.8 amps.

If I use something like this: TigerDirect Sunset would 20 amps of power blow anything up?
Also, would I be able to make it work with a 12 v and a voltage regulator? Will I blow up my LD29 ICs?

I don't want to set the student gallery on fire >.>