Augmented/diminished/sus/7 chords:
the notes in an augmented chord are all a major third apart. So A aug would consist of the following notes: A, C# and E# (which of course is more generally known as F). A diminished chord on the other hand consists of notes that are at intervals of a minor third to each other so the notes for this chord would be: A, C, E flat and G flat.
A chord described as sus (e.g. F#sus) means that the note which is a third above the root note is raised to a fourth. The chord of A major has the notes of A, C#, E, or root, third, fifth. If the C# (a third above) is raised to a D (now it's a fourth) then the chord becomes A sus. You can hear a nice repeated sus/non-sus chord pattern at the start of The Who's Pinball Wizard.
Add 2 means "add a second note", e.g. add a note that is a major second interval above the root. So if you were playing an A chord with an added 2nd, you would add a B (which is the second/next note after A) to the mix. If it was a D chord you would add an E. And so on. Add 9 is the exact same thing (if you count 9 tones from A you get to B again). A minor second interval would be a B flat and would sound nasty so you usually don't see that around much.
A7 means playing a standard A chord while adding a note to a chord that is 7 steps above the root note of the chord. So the 7th note in this case would be G since there are seven steps from A to G (count 'em and see). In this case the notes would be A, C#, E and G. A minor 7 would mean the same thing but the chord would be A minor, or A, C natural, E and G. Finally, A major 7 isn't the same thing as A7 though it sounds like it ought to be, the major 7 refers to the fact that the 7th note is a major 7th above the root. So the base chord would be A, C# and E and the added note would be G#.
Put a sus and 7th chord together and you get the distinctive chord from The Police's Walking on the Moon which uses a Gsus7, e.g. a chord made of G, C, D and F. The bass is playing a D by the way. It's also the opening chord of the Beatles' Hard Day's Night... hope that helps.