What should i do with my guinea pig?

My guinea pig had a baby 1 week and a half ago and I checked today and found out it was a boy... I really don't want to get rid of it because I've grown attached to it and its already used to me and likes me, and I only have on cage its 54in x 20 cage and I can't get another one... any ideas on how I can keep it without getting the mom pregnant?