1) Get several bikes. Think of this as a wonderful excuse.

2) Learn maintenance your own self. This limits your bills, gives you an appreciation for your bike, and I've found it makes riding more fun. It does require some investment in tools and time.

It sounds like you commute, since you're walking w/o a bike. Find a good beater at a local thrift-- since you've been riding awhile, you probably have some good notions about fit-- get Zinn and the art of (mt/road) Bike Maintanence, and tear the bike you bought apart, than put it back together.

I began maintaining my own bikes when I took the PFN into a shop to be serviced, and they laughed at my bike, then tried to sell me a new one. A little more direct than your problem, perhaps. But I'd be irritated as well, given your situation.