I cannot listen to this piece yet (no sound here at school), but I think I can address the theory question that you didn't get answered. (The idea of this forum is to be supportive and helpful, yeah?)
A Trio Sonata is a piece in Sonata form for two melodic instruments and a basso continuo. This means threes lines of melody, the bottom of which is for unspecified instrumentation. Two violins and basso continuo, or two flutes and BC, are quite common instumentations (Flute, Bassoon and BC is quite nice too!).
A fugue is... a large fughetta? Haha it's a bit hard to define. A fugue is a specific type of contrapuntal composition.
The fugue is a form which takes a main melodic theme (the Subject) and develops it polyphonically.
I have to run to make a rehearsal, but for now look at the wikipedia entry, it's not bad. Fugue - Wikipedia, the free encyclopedia
And PS don't worry about the lack of theory knowledge. Everyone starts out not knowing theory. But I would suggest that you study theory, preferably in a class situation (most community colleges have theory courses, for example), before attempting to compose a fugue. The fugue is one of the most difficult forms to master (I still struggle with it), and is kind of a right-of-passage for the composer, to be able to compose his first fugue.
Best of luck with your compositions!