I work at a petstore and I've owner 10 guinea pigs and I have 3 right now, and id recomend, getting another female for sure, or youll be having new babies in just a couple months. Introduce them SLOWLY, because guinea pigs will fight unknown piggies. You should put them in seperate cages next to eachother forlike a week, and then if that goes well and theres not too many threatening sounds, let them loose in a small room that's closed with nowhere they can hide, and watch them. Try this alottttt. And then put them in a big cage together and watch them, if its 2 females it probubly will work, but don't put 2 males together who didnt grow up together because they will fight. I hope it works!