tips for having sex after baby?

I love my husband and my son but our son is now 6.5 months old and we are attempting to get back into the swing of things. Yes, we have had sex in that time frame but not as much as either of us wish or desire. We used to have sex a couple times a week now we are lucky to get it on once a month. The attempts are complicated by the fact that our son is still not sleeping through the night (getting closer) and we currently live with his father (after heart-attack). Does anyone have any tips or words of wisdom?