How do you tell how many troops are donated in a week? I know if you go to your clan it has sections for "troops donated " and "troops received", is this on a per weekly basis? If yes, when is the start of the week?
The only ways to figure out how many troops a user have donated is through the panel you've described above (the Clan Screen).
As for the timings of the league resets, it does so every 2 weeks; at every other Monday midnight (US Eastern Time; EST -5:00 UTC). At the time, everybody loses their league placings and the counts (for donations and attacks/defenses) which are thus reset to 0.
As for challenger leagues, these reset at the end of every month, and the timers can be found in the ranking pages.
Note that the fortnightly reset does not affect trophy counts for Challenger League players. Only the monthly League reset will set all their trophy levels back to 5000. (For those underlings like me with less than 5000 trophies, this is nothing to worry about).
As suggested below, if you're keen on keeping track of tallys, count the troop numbers on the Clan screen at the end of every week and just simply subtract from the totals to find out the donations for a particular week.
With the troop count, is it count per housing space or actual troops? For example if a giant is donated does that count as 1 or 5? Also, is it possible to see what kind of troops were donated?
To simply put it: It's per storage count. This was changed a few months ago in an update (it used to be 'per troop').
So, donating a PEKKA now awards 25 to the respective count rather than 1.