Get a job and save up. I remember being in your position a few years ago; old enough to have grown up hobbies, but not old enough to easily pay for them.

You'd also be well advised to not fixate on upgrading the group, especially to Sora, and think more in terms of buying a whole new (To you, anyway) bike. You're more likely to find a sweet deal on a whole bike, and you'll probably find the upgrade to the wheels and frame to be worth it as well.