Fashion and dressing well arent my strong points,i woudnt even know where to start.
I would start by watching TV: Queer Eye For the Straight Guy on Bravo and What Not To Wear on TLC. They will give you a great overview of what clothes work for what types of people and why. And they are fun and will get you excited and motivated about improving your look, by showing you that is possible to go from zero to sixty by making just a few small changes.
Some books: Color For Men by Carole Jackson. A lot of this book is outdated, but the guidelines for determining which colors best complement your skin tone are timeless. The book is out of print, but your library or used book store probably have copies.
Off the Cuff by Carson Kressley. He’s the “Fashion Savant” on the aforemention Queer Eye show. It’s an irreverant and up-to-date guide to finding the clothes that best match your body, personality, and lifestyle. A two button rag of a shirt might work for college-Roark, but it might not work for you.
There are other “classic” books that you’ll see recommended on men’s clothing, like Style and the Man for example. It’s worth reading, but some of it is a bit outdated and the bulk of it irrelevant to most men, unless you wear a suit every day to work and get to shop for the latest couture in Milan and London (it actually has a directory of the best places to get clothing in Europe’s poshest cities…like I have that opportunity).
Read men’s style-oriented magazines like GQ, Esquire and the like. Cut out pictures of things you like from the magazines and bring them with you when you go shopping, so you can find looks that match the pictures. Don’t tell yourself “I could never wear that.” That’s just self-limiting defeatism. You are worthy of looking great.
Notice other people whom you consider snappy dressers and ask yourself what makes you evaluate them that way. More often than not, it’s two things (among others): their clothes actually fit them right, and they have cool accessories.
Another tip: Actually GO SHOPPING. And not always at Wal-Mart or JC Penny but at the expensive mall clothing stores. Doesn’t mean you have to buy anything, but get a feel for what is out there and what you like. And very important: TRY THINGS ON. Even if you only marginally like something, grab it and try it on anyway. You might be surprised at what looks good on you. Be more of an empiricist than a rationalist. You can talk yourself out of a piece of clothing, but you really don’t know if it works for you unless you have actual experiences trying it on. Have fun with it.
Within the constraints of your budget, buy the best quality garments you can afford. It’s a much better investment of your money to buy something that is classic, timeless, well-constructed, well-fitting and will last you… as opposed to some piece of junk that you’ll have to replace in six months because it’s coming apart.
Hope this helps.
P.S. It is also a plus if you have a fantastic credit limit and little abandon. 
P.P.S. Also, throwing away all your pleated casual pants would be a great start. 