If your problem is with the actual size of the texture, you could look into Thor's BigTexture and BigSprite class.
If the problem is with the slowness due to too many draw calls, try using vertex arrays.
If it's a mixture, you'll have to look into your own solution. Split the texture into multiples and use multiple vertex arrays (one for each texture), try to sort it as needed, only draw what's visible, etc.
Also a more descriptive explanation would be helpful.