Our dd had a lot of gas too... after bath, we did a lot of gentle bicycle legs to get rid of what we could before putting her down for the night. I also put Mylicon (brand name) or simethicone (active ingredient, many store brands have the same thing just not as pricey) in her last bottle of the day for almost a month, the nights that I skipped were not as comfortable for her, so I kept doing it almost every evening. Around 5 1/2 months, I stopped because she seemed to be able to pass gas without as much effort, and I haven't used it since!
Good luck,
Trish