The Peter St./Adelaide/Richmond area has a lot of bars. Not sure what kind of places you like but there is a lot there for all tastes.
For hotels I suggest staying on/near Yonge St, lots of stores & restaurants you can walk to from there. The Delta Chelsea is nice, and relatively inexpensive. If you want to go ballin do the Royal York (Front St.) or the Grand (Jarvis). The Royal York is old-world Victorian luxury style, while the Grand is new and modern. There are 2-story suites in the Grand that are super hot.
The Eaton Centre is cool for shopping, but if your GF loves to shop you might be in there for hours, its like 5 stories. I just took off to a bar the last time that happened.
Once you get there just leave your car, walk or cab everywhere. Cabs are easier and cheaper than paying for another pay parking lot or garage.
