You have to report to the company within 3 days normaly. then starting work depends upon the company policy. in the initial stages you can use rent a car and after RP you can buy urself. Internet and cable TV is providing by Qatar Telecom.
There are some good local service agencys in doha. you can use there service if require. they help you to arrange car, internet and telephone conection, setting home,and in other local needs.
In normal case your company will lookafter all your needs so no need to approch any and QL is there to help you at any time. post your comments then you will get the solution soon