Great question! There are pros and cons to all options.
As a start-up you have no $$...and it sounds like you may have no skills in regards to creating a website.
Without $$ you cannot hire an employee or freelancer (unless you are willing to take a loan).
But without a lot of skills it may be difficult to hire an intern as he or she is doing an intern to "learn."
All that being said college educated students with information technology degrees know a lot about helping you get your website set-up. If it's a simple website chances are they can help you get it up and running. And many are willing to work for free in order to build their portfolio of websites.
If you require more involved development work, shopping cart and autoresponder integration, an intern may not be the best choice. These projects require much more understanding of how these systems all integrate.
These are just a few of the things you need to consider. The last thing I would consider is your timing. You say your site will launch in January? Many internships fall on a semester basis which means your intern may not start until early to mid-January as most schools are finishing up their semester now. That being said there are a lot of students on winter break looking for an "externship" (think, mini-internship) that might be able to take on your project and complete it before they return to school in January.
Hope this helps!