I will start with the easy one. GOP expands its lead in the House significantly. Probably in the area of 20 seats.
GOP will take the Senate 51-49. This comes with a caveat though. If a candidate on their way to an easy win effectively takes their self out of the race with retarded comments it cannot be predicted.
Here is a list of Senators up for election. Ignore the commentary, its just the list I am worried about.
U.S. Senate Races
Dems currently hold a 55-45 edge in the Senate and I honestly dont see any way they keep the majority. I see the GOP picking up no less than 6 seats and could easily envision them winning 11.
A good article to outline some of the more interesting races early in the process.
2014 elections: 10 critical Senate races - James Hohmann - POLITICO.com