One size does not fit all. Bikes are usually sized by the standover clearance at the Top Tube. You can also size it by the reach from saddle to bars, this is a more critical dimension for getting into a comfortable riding position. You will probably need a large size.
Those specs are for a 7 speed bike. That will be adaquate for riding on most terrain but if you want to take it on steeper roads and trails you may want to use a wider and lower range of gears with an MTB style triple chainring.
When you are buying a new bike it is much easier to negotiate a discount on extras rather than get cash off the basic price.