On a limited budget, well my idea would be an early bedtime for baby that night. That afternoon go to Albertsons, they always have strawberries dipped in Chocolate, get a few, a bottle of champagne, something he really likes for dinner and some bubblebath and some type of body oil.
Before he comes home from work, set the mood: fix dinner, set the table with a candle, his favorite music or some good sexy soft music, lights low and give him a nice romantic dinner, have a a fun sexy movie ready to watch. Talk about the things you used to talk about when you were dating or the things you both like to do and forget work, problems and baby even for 1 hr. Good luck and have fun, can't get pregnant you already are.