I don't know of any startups that outsource their development. I know of startups that pull in the assistance from other studios or extremely talented contractors nearby, although the last startup I was in, we did that early on (seed funding stage) and the studio that worked for us did a terrible job. It was a nightmare and in the end, I was sent in to fix all of their problems in Flash. It was a combination of incompetence on behalf of the studio, and they weren't physically present, so the pressure on them for succeeding wasn't as strong as if they were in the same room as us.
What happens if you outsource? You'll either save on two things: time and money. If you save on time, you're going to pay a high price for good quality. If you skip out on price, you're going to get crappy code, and you will spend just as much time explaining to the developers how to build your product. And I know of startups at my school that have re-written their entire code base simply because of how rapidly they're iterating. Can you imagine what it'll be like trying to get a company from another country to write your initial code base, and then eventually hiring someone to manage it? I'm guessing it will be a nightmare. There's a reason why companies like Google and Facebook are desperate for top engineers, it's because the quality becomes a competitive advantage, it's pretty important in a startup and investors know this. That's why so much emphasis is on your team, and not necessarily your idea.
Why not stick it out for a month and write your own prototype? It will take the same amount of time to find, hire, explain, review, and finalize code being done by someone else.
I want to say that any ambitious angel investor or VC will NOT fund you if you outsource your development. Why would they? You aren't bringing much to the table at that point. And if your only advantage is some code that was written, well I'm sure your angel or VC already has several programmers in their rolodex that could do the same thing, with better code, much faster. So you'll have a very hard time convincing someone why they should invest in you, instead of just pass the idea off to one of their existing startups to work on if their current gig is failing.
I don't want to discourage you from pursuing your idea. Just keep all of this in mind when you make your decision.