Okay, so it would be best if you could eventually adopt her a girlfriend so they can keep eachother happy

the minimum for one or two piggies is 7.5 square feet of floor space. You won't find a pet store cage that big, so it's easiest to build one. You need to feed her veggies two times a day and you need to research which veggies are best and how often they should be fed. Don't use any pellet food that has extra stuff in it. Pellets ONLY. They really like places to hide under, so boxes and towel tents are perfect for them.
Romain, other lettuces, cilantro, and bell peppers can be fed daily with other veggies and the Occational fruit as well. She will also need unlimited access to grass hays (not alfalfa.)
I recommend reading and learning from this site: guineapigpages.com
Edit: oh yeah, and an hour of floor time every day would be perfect. If she could stay out even longer that would be better!