First of all, DO NOT sell it to a music store, they'll rip you off.
If the guitar is in excellent condition (good action, no chips in the paint, no cracks, good tuners, etc..), and if new it costs around 600-800...you should try to sell it for about 350-500, depending on its condition.
Post a picture if possible...you should also know what wood is it made of. I know that one has a spruce top and mahogany sides, but I don't know what the fingerboard is made of.
Try to go to "Steve's" guitar store web site. They have a few stores and must have a web site. They sell all kinds of guitars, I think they may even buy/sell used guitars.