Hi viper1991,
There are some relevant details to your story that you haven't posted here, including your improvements thus far and the various aspects of your prior studies that were not handled in a realistic and test-like fashion. The short answer to your question is YES, you can certainly improve to a 650+ (and doing so could very well take less than 6 months). All of that is dependent on studying in the most practical and realistic manner possible though. If you don't make additional adjustments to how you're studying, then your score will not improve.
GMAT assassins aren't born, they're made,
Rich