Well, it depends. You can still use your amp, and it will probably sound OK, but are you planning on playing with other people any time soon? If you are, you'll want a bigger amp, and I think it's better to invest early in good 50 watt (or so) tube amp early. That said, I'de think about it if I were you, for a few resons:

• Amps cost money, you probably won't get a lot of money for your Dean amp if you trade it in, so you'll be footing most of the bill.
  


• Tube amps (which most people agree have the best tone) are HEAVY, if you're adverse to the idea of lugging around about a pound a watt (give or take a couple ounces), you may want to wait.
  


• You allready have an amp. If you aren't planning on playing out or jamming with some friends in the near future, then a large amp will only annoy the neigbors (and tube amps are ment to be turned up a bit, so they get less than ideal tone at low volumes).
  

So that's some stuff to think on. If you do decide to buy a larger amp try to sit down with a guitar that's similar in design to yours and play with it for a while. Try different amps and see what sounds best to you. If you go for about 50-60 watts of tube amp you'll have something that will cut through if you're playing with friends or a small show, and can be miced for larger venues. If you're just going to be playing alone for a while though, it's probably a good idea to wait and invest a little more money into the guitar. Try to keep in mind though that tone and playability is what's most important. Make your self happy, not the salesman.