change of strut ? (2000 accord ex v6)

I have 2000 accord sedan ex v6. One month ago, I went to "pepboys" and got oil and transmission fluid changed. After works done, they gave me a couple of paper. What it said is that front and rear struts are leaking. And when I paid at the cashier, they took the paper back, and they didn't tell anything about that.
What I want to know is that

1. Don't they(pepboys) tell anything other than I asked to do?
2. When should I change strut or shock ?
I really do not have a ideal of strut and shock.
3. If I change strut or shock, what brand should I choose to get factory ride height? I do not want to lower my car, but want to get comfort ride.
(I think current mine is gas shock. right?)
4. How much are they for change ?
5. Actually I'm gonna change tires and wheels, is it good timing to change all together or should it be after or before ?

I'm a beginner of car care although I've driven for 10 years.
Please, leave answers.
thank you.