I don't need the exact figure, I only want a rough estimation.
Not all that much.
Looking at his raw data (from searching here), he donated a total of $19,040 since 2001, which averages $1,464 a year. (This doesn't seem to include the inauguration donation, though).
To add to Bobson's actual answer, the subtext of the question is that Klain's nomination may have been influenced by his donations. While not exactly unheard of in Washington, DC; in this case it is clearly evidently NOT the case, as Klain was already an extremely influential political figure in Democratic politics, including in Obama Administration:
- Very extensive government career prior to 2000
- Chief of Staff to VP Al Gore
- possible replacement for White House Chief of Staff Rahm Emanuel
- Chief of Staff to Vice President Joe Biden
- "In 1994, Time named Klain one of the "50 most promising leaders in America" under the age of 40. In 1999, Washingtonian magazine named him the top lawyer in Washington under the age of 40, and the American Bar Association's Barrister magazine named him one of the top 20 young lawyers nationwide."