Re: visa for Dubai if stay is a week?
You can get a tourist visa, which is valid for 14 days, and would be the cheapest in this case. You would have to get that in advance, through your travel agent, or even your airline can sponsor you, if you are using Emirates or Etihad. If you choose to get a visa on arrival, then on a Pakistani passport, the maximum you can get is a transit visa, which is an overnight stay pass.
A decent hotel with meals and travel will probably cost around AED 500 per day for a family of 3. Id recommend renting a car as opposed to using cabs. It will be much cheaper, and will give you a lot more flexibility.