7k is a ton of money. Don't do it. If the GREs don't seem manageable to you, then know that you'll be down struggle street for the MFE program. Buy a range of exercise books, including the books written by ETS (they tell you everything possible that can be on the GREs since they write it). Getting a range of textbooks is important because the style and difficulty of questions will differ between them. I think there are also free online GRE exercises... would be worth searching.
To have a chance of getting into a good program, my understanding is that the scores you need are:
Q - 165+
V - 155+ (If English isn't your native language. If it is, the required score is probably lower or even negligible)
AWA - 3.5+ (Same idea as the V score)
Hope this helps.
J