The best thing to do would be to adjust the two shocks on the rear tire, so maybe try and find a replacement tool? Oh wait, here's one. Adjusting the shocks was the first thing I did during my first longer ride and it made a huge difference. You don't need to buy new parts to make your bike ride better, you just need to adjust it. I suppose you could always stand up or lift yourself off the seat when you're going to hit a huge bump, too. That was some advice I picked up during my motorcycle training class it's worth it. It keeps your eyes on the road too 