Time frame for developing shopping E-Commarce solution?

Question

Hello All,

I am giving following solution to client, I want to know how much time frame I should commit to client. Client knows my expertise which also I am going to mention in this topic. Please give me some idea if your android developer.

 

Shopping Cart Android App for end users

Android App for  back office users for getting orders and other stuffs.

Android app for supplier to get order and do action on same.

Shopping Cart website in MVC.

Shopping Cart Back office windows app in C#.

Database is in SQL Server.

 

My language experience in years as follow,

C#.net : 8 years

Android: Almost new in this.

MVC:  Almost new in this.

SQL Server: 8 years.

 

I have 9 years of experience in Retail software industries. So logic and requirement is not big deal for me.