This bike seems to be a relatively cheap bike made for someone to toodle around town on occasionally. You seem to be interested in more than that. If you have $800 total to spend, consider a used touring bike, like a Trek 520, or Fuji, or Cannondale T800. You can find them on Ebay all the time. Also look at a Windsor touring bike from BikesDirect.
The reason I suggest a touring bike is that they're usually built strong, which is good for us Clydesdales, and are good bikes for commuting and weekend rides, as well as for touring. They usually have cantilever or V-brakes, 36 spoke wheels, and room for wider tires, which is good for Clydesdales, as well as for occasional off-road riding. They will have wide-range gears, although you might need to swap for a lower-range crankset if you ever go touring. You might be able to get a good touring bike and have enough money left for a Brooks saddle and one or two other mods.
There are other touring bikes. One would be a Surly LHT, but it seems to be more difficult to find one that's much less than new (They're only $900 new, which, to me, is a TERRIFIC deal.)
Just a thought.