Broke triathlete looking to upgrade bike.
So I'm a BROKE high school junior, I enjoy riding my bike around, and on occasion I compete in local Triathalons using this bike. I've done 2 sprint triathlons using this exact bike. I have a full Olympic-distance tri in August that I've started training for. The bike works fine most of the time, brakes, gear system, wheels all work fine (besides brakes being a little slow and gears being a little finicky). But I'm looking to do some upgrades before my race to be able to get a little more speed/performance from it. I don't know much about upgrading bikes, but I am open to learning anything and everything I can. I just need a place to start. I don't have thousands to spend on a bike, but I will be working a few jobs during the summer, so I can drop a couple of hundred if needed onto it. If anyone has any ideas for online resources to learn or possible upgrades I can do. I bought it off of Facebook Marketplace about a year ago, so I'm at least its second owner. I believe it is a GT GTR series 4, but I could be wrong.