Question on omega squared...please help!

I have just obtained the output for a one way repeated measures ANOVA and have read that it is useful to report the size of the effect using omega squared (w2). For example, F (1.88. 218.29) = 42.64; p = < 0.05, w2 = ??. COuld you tell me how to find the value for omega squared as I cannot find it in the ANOVA output? Also does it have to be reported?

Many thanks...