The best thing you could give a cavy other than space/large cage would be a friend. Guinea pigs are social animals and interact with guinea pigs very well.
Boys can live with Boys
Girls can live with Girls
Neutered Boys can live with Girls
Guinea Pig Toys and Play
Other than that, about her diet, you may want to read the sticky tags in this forum:
http://www.guineapigcages.com/forum/diet-nutrition/
Especially this thread:
http://www.guineapigcages.com/forum/...tml#post254730
Otherwise...that should be it.
I'm sure you'd help Penny out as much as possible! (-: