Carolyn,
1 - it is not the case that Yahoo is the only account you can use for groups - though they like to make it look that way.

2 - can you tell me which groups it is where only your Yahoo email account is showing up?

3 - When you go online for one of those groups and you do Edit Membership, the available email addresses should show up with round circles to the left (where you can pick one). Which addresses show up there?

If you can get me these answers first, maybe we can first address the issue with only being able to use the Yahoo email account. Then after that we can work on getting your name to show up.

Kitty