You can't track rep you give but you should have gone for the yellow membership, not the grey. It's much better value or money and you get all the perks.
I'm not sure I even know what. A 'premium' member gets.
You can see your reps received by going to user cp
Yeah I really don't know why I did the 5 and not the $10 membership. I have found the cp and where it shows what post where rep'd. But I thought it would include the name of who rep'd me. Because I can't tell just by some of the comments.