For your weight, a 159 is too big for you, especially if you plan to ride in the park. You need a wide board though. I would suggest a 152-156 for your weight. I can't really suggest a board though, seeing your price range is very low. If you decide to spend more money, look into the Rome Slash 154 or 156. I think that will suit your needs very well.
You can find last years Forum Recon Wide for $150, then you can pair it up with some bindings from last year too.