Choosing Hosting Company

Hi There,
I have just purchased the yearly WPMU package. I will be planing to set up a website platform that allows users to sign up for their own lead building website for their business.
So I am envisioning that I will have a lot of people register for the website package.
Obviously before I start developing the structure, I will need to install the Wordpress installation on my host.
I currently have a Hostgator BABY PLAN account. But I am thinking I may need to just open a new account for this on a better host plan...
What do you suggest I do??
Thank you and look forward to your response?