The language probably won't matter so much. I think you will have just as big a job in business development, design and marketing.

So why not look for a technical cofounder who is quite competent in either python or ruby. Then you can have them do the bulk of the coding and possibly oversee some development by other freelancer/s. Head to a ruby or python meetup, ask if you can jump up for 2 minutes and introduce yourself. There will probably be cofounder speed dating type events in your local area as well.

To pipe up about languages and frameworks, make sure when you build that you are considering Service Oriented Architecture (SOA) so when the time comes you are able to break off the pieces that experience higher load. http://en.wikipedia.org/wiki/Service-oriented_architecture