You don't have to swap out the whole crankset. Since you said you don't really use the 50 that much, why not try swapping out the 34 for a 36 or 38 and leave the 50 alone.

I found the 34 w/ 12-15 (700c wheels) annoying and swapped for a 36. I didn't want to go bigger because I do have some hills where I get in my biggest cog.

There's nothing wrong with running 50/38 up front w/ only a 12 tooth difference. 'Cross bikes often come with just a 8 tooth difference (46/38 is common).

Cost would be less than $30-40.

http://www.amazon.com/FSA-Road-110mm...7804090&sr=1-2