BTW, the 12-30 10 speed cassette works great with the short cage 105 derailleur. Combine that with a compact crankset and you should be able to climb some hills. As far as the handlebar, go find an adjustable stem of the appropriate length, then try different angles. Once you find something that works, you can buy a good lightweight stem that replicates the adjustable stem.

And finally, go get a professional fit done. Sometimes, people reduce reach and then end up with neck problems.