Brake Fluid Leak problems of the 2002 Volkswagen New Beetle

I bought my New Beetle brand new in August 2001. The day after I brought it home (over 2 hours away), the check engine light came on. I called the dealer and they said it didn't mean anything unless it was flashing so I thought nothing of it. 2 months later my abs went out while I was an hour from my house and it had to be towed and replaced. The windows continually go up and down by themself but the dealer can't fix it. I took my car back to the dealer yesterday because it was leaking brake fluid and told them again about the cel light. They then told me I needed to have the mass air flow sensor replace (nearly $400) and that is why my car has been downshifting by itself and losing power while driving. This makes me feel unsafe to drive the car that I had wanted for so long. Dt.