Hi There,
I have gone through your project description and understood your requirements properly , although to tell you proper estimated time duration i would be needing one document from your end i.e., FRS(Functional Requirement Specification) .
I believe i have the right team and people for this kind and job and will surely be capable of doing this and delivering a quality product to you .
If you could just drop me a message on freelancer chat then we can have a detailed conversation on this and even if a Skype meeting is possible to make you sure that we can provide the features that you are looking for in the market .
hoping to hear from you soon !!
cheers !!