This is a good problem to have. We're in the same position with our product Widgetic.

My advice would be to go through this article by Paul Graham:
http://paulgraham.com/ds.html.

I did a resume of what you need, here:

**Fire** - Focus on a deliberately narrow market (subsets of users). It's like keeping a fire contained at first to get it really hot before adding more logs.

**Consult** - pick a single user and act as if they were consultants building something just for that one user. The initial user serves as the form for your mold; keep tweaking till you fit their needs perfectly.

As you can see, this also seems the best approach - which not many products are lucky to have - to pick a specific target user group and focus on that initially, to get as much of that market first.