I have a hard time swallowing the price of Photoshop for such a limited application, when I'd probably be using less than 25% of what it does...
You can try pixelmator(1) (mac only) or pixel(2) (cross platform).
For working with images: http://flyingmeat.com/acorn/
I believe there are some "lite" versions of photoshop out there for cheaper prices, though...
There were numerous sites full of these on the web when I got started, and I'm sure there still are. Here's an example of what you're looking for:
http://psd.tutsplus.com/tutorials/tools-tips/use-over-40-adv...
Basically, it shows you how to create a concrete effect or object. The point is not to create the object itself, but to learn the techniques used to create the object so that when you want to create your own stuff, you have enough of a repertoire of techniques to achieve what you want.
As for places to get design critiques, I'm afraid I'm a bit stumped for that for them moment, since all the design communities that I belonged to back when I got started (around 1998) have died out since, but I would guess you can find them by starting with designer-oriented sites like smashing magazine or this psdtuts, and locating the forums attached to them.
Edit: I assume that you know where to learn CSS.
When you're done, get someone to convert it to HTML. Doing so yourself is a waste of your time.
I'm no designer either, yet I can make some decent designs (e.g. http://danieltenner.com) that, imho, look far from horrible.
The key is to practice and to get comments/criticisms from other people. It also helps to join a web designer forum and offer critiques of other people's designs. What you need is basically to train up your own internal critical engine so that you can point out the flaws in your own designs and correct them.
Being able to make things look good is a pretty useful skill in all walks of life, I'd recommend learning it rather than trying to outsource it.