Please help!

I'm not ready to move my baby to his nursery yet. However, he's 3 months and is almost too big for his arms reach co sleeper and almost rolling over. I do not want him in our bed but I can't seem to find anything like the co sleeper that'll fit him. I've looked into pack n plays but I don't think the sides are tall enough for it to last him as long as I'd want and the bassinet part is up to 15lbs which he is already close to. Suggestions, please??