If I am reading it correctly, haarish1984 is referring to the MBA course fee, which will easily dwarf any money he will spend on any GMAT course. One thing to keep in mind is that GMAT scores are only valid for 5 years, so you may be getting close to their validity.
670 is a good score, and generally someone who is scoring in that range can push their scores to 700+, which is a solid place to be for applying to business schools.
I would recommend you to get some more information about the typical cost of the MBA program at the business schools that you are considering. Also, I would look in to scholarship options. And finally, you may want to think of joining an MBA program locally that allows you to work at the same time.
Cheers,
Dabral