If your account was compromised the hacker would have harvested all your contacts details. Once he has them there is no need for him/her to go back into your account. He has the list of contacts which he can now use when ever he wants. The hacker will now spoof your email address to make it look like the emails are being sent by you.
Deleting your account will make no difference as the emails are not coming from your account.
What you should do is set up a new email address and stop using the "hacked" account and advise all your contacts to delete any email that they may receive from that account and mark them as spam.
If you do set up a new email account you should use an email client such as Windows Live Mail or Thundrbird and store your contacts details on that. Do not store your contacts on the email server and that way if the account is hacked again the hacker can not get your contacts email addresses.