This is what I do when my renders start to choke:

--Make sure all background tasks are killed unless they're necessary (learned that trick from playing The Sims LOL!)
--Don't have any messengers open.
--Try not to open any webpages to keep from lagging up your machine.
--Save the poser file and restart the program to give it a fresh start before rendering.

These things usually help get my renders movin' and hopefully they do the same for you. I haven't the slightest idea what specs my laptop has but if I can render a 1275x800 image with two figures (close-up) and several props in about 5 hours on it, then it must be pretty good LOL!