You will get a lot of use on USB on the freeband.
There is a lot of LSB used but the good long distance DX, not talking about across North America, talking about South Africa, New Zealand, Europe etc etc you will get on 27.555 USB as previously mentioned.
That rig will do you justice and you will have alot of fun.
You definately need to improve your antenna system, some good reccomendations have all ready been posted.
How high should you install the antenna? "Take it to the moon", but at least 36 feet to the feed point. Height is might on HF and your antenna is the most important part of your station.
You will be suprised what a good antenna and 12 watts on SSB will do.