If you're bursting at the seams, then you need to think big! What's your next step?
If you've outgrown your premises, then there's lots to think about if you want to extend. There are tips for you here, to help you deal with planning issues.
You'll also need to look at your tenure. That could affect whether you can extend and get funding. Not sure what your tenure is? We've got that covered too.
Plus there's loads of advice to help you make more money from what you've got.
So get going...