Greetings Eva,
I'm Barbara from IQRIA company, me and project manager - both speaking fluently English, all my team consist high professional developer ( we are small company, so it's simple to follow the quality), we specialize in sophisticated technology, and huge bonus for you - you will get high european quality for no european rate as my team located in Ukraine (so no indian bullshit).
I like the script you choose - it's totally fit our professional area, about PayPal integration - we've recently completed an invoicing and inventory processing system for one of our customers where were full integration with PayPal, Amazon and Ebay, so we already have set of modules that make creation of such applications easier and faster.
We need couple dayss to check the code and make modifications, you've asked. About Integration Social Media, Payment Processor, Cloud Storage - again, need to check, for my very rough assessment - 1 week each. But need to discuss the details with my Pm first.
To go for it, let's hop on a Skype or phone on Monday 15th @10AM. If time isn't convenient, could you please give me another timeslot.
Thank you, see you