Regarding the ABS module, I am assuming that you have already diagnosed this as the problem (versus other stuff, like the wheel speed sensors). As long as you get the correct part number and are comfortable wrenching brake lines, you can do this yourself. Also, you typically can not get the ABS unit in separate parts - you can buy the whole thing or nothing, you can't just buy the motor unless you go to a junk yard.

Also, don't forget to do a few ABS stops (like on a gravel road) after you bleed the brakes and then re-bleed the brakes.