Alright, I know you said that money is an issue (for shows? Or everything), but this is what I would do and DID do for a while: I started out riding at one barn where I rode for 5 1/2 years. I loved it- I loved the people, the horses, the instructor, BUT I wasn't improving AT ALL once I had the basic walk/trot/canter down. It wasn't a jumping barn, and Medal and Equitation classes are my passion. But I didn't want to leave that barn, sooo I rode there once every other week, and started taking lessons at another barn that gave jumping lessons every week. Eventually I completely switched over to the other barn because I was just wasting my money at the first barn when I wasn't improving at all, and even though it was hard to leave, I knew I did the right thing for myself and for my riding. I'm sure you could find a barn where you could work off some of the costs. At the barn I'm at now, I was able to work off the costs of riding on my own time (out of lessons) and my instructor let me borrow her old show boots and jacket for the shows last summer, which lowered the cost of showing by a couple hundred dollars.
Sooooo now that I'm done rambling on, my point is, why don't you continue riding at that barn and try a couple lessons at another? If it's really worth it for your riding, and if you truly want to improve past what they are able to teach you (be it the horses or the instructors), then I would switch barns. I'd love to ride in some Maclay classes in the far-off future, but with the first barn there was no way they could help me achieve my dreams, even if they wanted to, because they were a dressage barn. So maybe see if you could ride at both?