There's no need to worry! AOL's email addys are entirely separate from their BB service. They are part of AOL's free Web Services and continue in perpetuity. You don't need to do a thing!
Aside: As it happens, your O2 email addy is similar. It is also entirely separate from your BB.
1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU BB => 2010: Orange 16 Meg LLU BB