Online accounts are only good for one tax return. Each tax return requires its own account with a different user ID and password.
The CD/download versions that install on your computer can file multiple returns, just start a new tax return form the Top menu bar File menu.
Save your money! You can use the same version of Turbo Tax you installed on your computer for your use for her return, you just need to select the "start a new return" option when you open the application. Likewise the application includes five free federal eFiles so you should be covered.