Which technologies i should learn & use

Hi,
I am working on a project, which Consists of an desktop client, online sql database & one website. I use c# as main language. I don't have much experiance with wed devlopment. for achieving following features to above mentioned project, what should i learn? what service should i use? please advice

1. A secure channel for communication between desktop client & online sql database, which actually works as a software license database.
2. A repository for addons

I prefer microsoft technologies.

Thanks in advance.