contribution form login/account creation message

[boulderfuzz]

I have a beef with the message "Please enter a user name to create an account . If you already have an account, please login before completing this form." displayed on contribution forms which require a user to login to the CMS.  My users are always running into problems with our membership signup page because they don't understand the login/account creation process prompted by this message.  Everyone fails to read the help box and tries to login using the displayed registration form.  If they do read and understand the alert box, the default "account already exists" message (discussed and fixed in http://forum.civicrm.org/index.php/topic,30939.0.html) is still confusing.  We lose members weekly because people get flummoxed by this faulty process/messaging and just give up.

Here's the rub - I'm running Civi 3.3.2 and need to stay there indefinitely.  I understand from http://forum.civicrm.org/index.php/topic,30939.0.html that a more helpful message was implemented in 4.3.0 but I cannot upgrade.  What can be done for a 3.3.2 user like me?

Ultimately, I think this process would be far more user friendly if it behaved like the following:
"You must be logged in to this website to fill out this form. Enter your email address here: ___ <submit button>"
if account exists: "Enter your password here, or reset your password".
if no account: "You must create a new account" ... and display the existing username/password + check availability subform.

If that's too difficult, then I'd like to change the  helpbox text to something like:
"You must be logged in to this website to fill out this form. If you already have an account, <a href='%1'>please login</a> before completing this form. Otherwise, use the below to create a NEW account."

Is there a patch lying around that I can customize? I understand that alterations to /modules/civicrm/templates/CRM/common/CMSUser.tpl, but I have no idea exactly which lines to change and how (I don't know Javascript).

Thanks in advance!