I agree with sstorkel in that you probably need a better 32mm tire, not just a narrower tire. (You can get a 25mm tire that rides like crap and a 32mm tire that feels great, and you'd think that wider tires were better.)
I'm a fan of the Panaracer Pasela TG folding bead tires. They have the feel of an expensive handmade tire without the punch to the wallet. I've been riding 32s for the past couple years and don't think I'll go back to 28s or lower. The shock absorption of the 32mm tire over bad roads is just too much to try and match in a narrower tire.
As for the top end gearing, I'm going to tell you exactly what you don't want to hear: Work on your cadence.
Unless your average speed is above 21mph, that 48/11 combo is turning less than 60rpm.
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"I feel like my world was classier before I found cyclocross."
- Mandi M.