As Chuck says, you're confusing the laptop's memory with its hard disk. Given that, I would strongly suggest that you DON'T try to sort this out yourself. Instead, take it to an IT professional who can sort everything out for you.
As a recommendation, forget about Vista completely - Windows 7 is miles better in every way. So tell the IT pro that you want to do the following:
1) back up your user files (e.g. documents, photos, music etc) from the Vista partition;
2) delete the Vista partition
3) extend the Windows 7 partition so that it uses the whole of the hard disk - the IT pro will have utilities to do this;
4) restore the user documents from the recently removed Vista partition onto the Windows 7 partition.
Typically, this would take someone like Chuck or me less than half an hour. I'd probably charge you £50.