I am budgeting to hire a designer, having accepted that I, for once, am not good at something. Graphic design traumatizes me: I have photoshop, gimp, paint.net and inkscape. It will take an act of God to help me figure any of it out.
In the last couple of months I've come along decently (working in the few spare hours I have!). I recommend that you narrow down to ONE package, IE Photoshop, and then start doing online tutorials.
There is a wonderful collection available to start with, my favorite place are the *tuts.com sites. psdtuts.com or nettuts.com
Knowing the tools is a part of the package, yes, but there is more to design than knowing how to use the software. A designer with an eye for aesthetics and an understanding of both your product and your target users can be a very valuable asset.
This is an excellent point. I am in the same boat. At a pinch, I can bluff, hack or brute force my way through pretty much anything to do with programming, sysadmin, databases, whatever. Not as fast as an expert, ugly as hell, but it'll work. Mostly, heh.
This doesn't cut it for graphic design, however. When we're talking about the aesthetic appeal of a web site, it needs a real artist, an aesthete, a professional. It needs to be done well, and it needs to be done right - mashing stuff together is not an option. "Ugly but works" is inapplicable and anyway unacceptable.
Know your limitations. The front end is not the back end, and "good enough" is not good enough. Hire a pro, choose them carefully, and get opinions from non-techies before you commit. If you're serious, nothing else will do.