Finding the power difference of the current source E1?
I would work out the problem with variables for the terms you don't know.  It's possible that those terms cancel out.  For example, Ig * E1 is a constant, and may cancel out for the change in power that you are trying to find.  Besides, even if it's impossible because your teacher made a mistake, you can solve it in seconds once you get the missing information, if you already have the full equation.

Note that people won't give full solutions to homework problems on this forum, and won't really provide help, if you haven't shown a significant amount of effort in trying to solve it yourself.