Hi Nicole, and welcome to Mothering!! Congratulations on your pending arrival. You have definitely come to the right place for cosleeping advice!
There are several options for cosleeping: as described above you can attach your crib to the bed by either putting it in the corner and pushing the bed up against it, or others have found ways to fasten the crib to the side of a "free standing" bed. You can also buy an "arms reach cosleeper" (do a search for that and you'll find the link) which is specially designed for cosleeping. Or you could just get a bassinet or pram and put that next to your side of the bed, though your baby will probably outgrow them after a couple of months, but by that time some people who hesitated at first find they are ready to have their baby in their bed.
My DD has slept with me since the day she was born. In the hospital she slept on my chest. My DH and I are both very "aware" sleepers, and studies have shown that it is a very rare thing for a non-drinking, non-smoking, non-medicated parent to roll onto their child. So we have always had her in our bed and at six months we still can't imagine her being anywhere else!!
A queen size bed is fine, and a king even better! We used thin cotton blankets in layers, rather than a "poofy" comforter, and we've never had a problem with DD in our bed. I'm just saying this in case you are tempted, or you might find, as many here did, that you went and bought these cribs and sidecar sleepers but never ended up using them!!