Crimson Lass...  You know I hate to see a beautiful lady so distressed.  Just go to the account manager tab at the top and under that click on edit account information.  You can easily change the e-mail associated with your log in.  
The bigger problem may be to change it on you review page.  You'll probably need to file a "Problem Report" with TER.  I don't know (kind of doubt) if it changes automatically.  
Get your new adress working & set the wheels in motion.
A Fav provider had her Hotmail account hacked...  techies don't call it hacked they call it something else...  someone breaks or figures out your pass word, changes it & you can no longer access your own e-mail.  She spent hours with HM, but they ultimately did not reset it for her.  She had to create a new e-mail account.  Use a more secure pass word.  
skb

Don't close your Yahoo account.  Upgrade it so you can setup mail forwarding to your new account (after you open one).  That way any old clients' email will still be forwarded to you.

Lass,

You are an intelligent lady....... and you are JUST discovering that Yahoo sucks?!!

Now, speaking of sucking......(and I can offer some licks)!

I have to respectfully disagree.  I've had Yahoo accounts for many years with no problem.
I don't know what the bad guys are getting out of cracking ladies pass words.  But This is the second one this mponth.  This is a growing problem...  once the cracker changes your pass word, you never get your account back.
Actually, Yahoo just had me create New security notices & link to other accounts.    
skb