i don't know foldi, things can get pricey quickly with these things, you need to hire somebody to code it for you, look for a coder in one of the freelancing websites like odesk, you got to go with a foreigner to be affordable, western hackers are real expensive, you got to get lucky to find someone good and not sink your money with no progress, you got to stay on top of it and set milestones, basically be the project manager yourself which is no easy thing
there's also smaller boutique shops around the us that can code it for you but that'll run you around 20k-30k, dealing with americans, better communications etc but pricey, silicon valley shops will run you like 100k like gigster.com
dropbox bought an app in 2013 for $100 million and yesterday announced they'll discontinue it, imagine the reach they have and they couldn't make it work, apps business is very hard foldi, unless you got a strong plan to support it after envelopment it will not be worth it
best would be to hack it yourself or find a partner to do it for you while you bring something else to the table