^^^^ Unless there is something that can be changed about the amount you are hauling, I wouldn't expect any improvement on a road bike. In fact, the road bike would likely be more adversely affected (handling with load) and more limited in its gearing options.

However, I agree that you may be more comfy in all of those hills on something a little more suited to that kind of riding. I would suggest a touring or perhaps cyclocross bike. If budget is a concern and you have some basic mechanical skills, it is hard to beat bikesdirect.com

http://www.bikesdirect.com/products/windsor/tourist.htm
http://www.bikesdirect.com/products/..._cross_cx3.htm