Seven weeks is to young to be away from mom and littermates, but what is done is done, and it's important to take steps to ensure she will be well balanced.
When you take her out to do her business, say "go potty" when she starts (not before!) to pee or poo. Praise her verbally, but not to excitedly, and pet her to reward her. Do this every time she starts to potty. After a while of consistency, she will learn to go on command.
At her age, she should be going out to do her business every 2-3 hours. I do not advise using puppy pads, but some people think they are wonderful.
Also, make sure you take her (hand carried) to meet as many people as possible, to as many places as possible, to well socialize her.
There is more info on house training here:
LDT House Training