if i purchase the windows profi plan for 1 month, can i get a shopping cart with that too? and if i get it for 1 month, is my server terminated after that? or do i just pay for another month?

You'll pay for the next mont then.

Unfortunately there is no any pre-installed scritps at Windows-based hosting.
But you can install shopping cart by yourself. If you can't do this we can install it for you.