Staying Bard is an obvious choice. Bards really aren't made for multiclassing, as they have many talents. That's good if you value your versatility.
You could, of course, become a virtuoso, improving your bardic music ability with the virtuoso performances, but you'd have a crappy BAB and your bardic knowledge would improve no further. That's good if you want to be a real good performer
You could also become an arcane archer. Your talents with the bow would greatly improve, you'd have BAB as a fighter and good saves, but most of the stuff that make a bard a bard (bardic knowledge, spells) would cease to get better. That's good if you want to improve your skills with your bow.
You could become a dragon disciple (if you speak draconic and put all your skill points in the next level-up into Knowledge(Arcana)). Your usual talents as a bard would all but cease (some bonus spells, but you won't get higher spell levels), but you would get some cool abilities, like bite and claw attacks, natural armor, better hit dice, ability boosts, a breath weapon, wings.... That's gould if you want to have a real special character.