How to find the power supplied by the ideal current source?
\$P=VI\$
If you know the current that is supplied by the current source, all you need to do is find the voltage across the current source. You can do that by applying Kirchhoff's Voltage Law on any of the 2 bottom loops, using the mesh / loop currents you had already found. Pay attention to the currents' and voltages' polarity!

Good luck :)