That's a great idea!! Playing in a quintet will make you a much better musician because it forces you to listen in a way we're not used to. When I started our quintet, I approached my trumpet teacher, and he made me a deal, since all of his music was completely scattered all over his office and unorganized, he said if I organized it, he'd let me get whatever I'd like. So approach your trumpet teacher or another experienced brass player, you probably won't have to clean their office, but it always helps
Slowly over time you'll build your own collection, there are some great sites out there for brass lit, including Robert King, BVD Press, and Hickeys, best of luck!!