Baby bunnies can be fairly easy to bond, but when they reach sexual maturity ( 5 months or earlier) they will have to be separated to prevent fighting – which can lead to serious injuries. In order to bond rabbits that have reached sexual maturity, they both have to be spayed or neutered. So, if you got another bunny now, she could be with your bunny for a short while, but they would have to be separated in a couple of months, then re-bonded after their surgeries and recuperation periods. The easier option may be to wait until your rabbit is spayed, then get another rabbit to be her companion at that point. If you get a rabbit from a rescue, most or all of them will be spayed or neutered, which save you trouble and expense. As RosieSatellite said, it is generally easier to bond a female with a male, spayed and neutered, of course.
Here is one good article on bonding:
http://rabbit.org/faq-bonding-multiple-rabbits/