#1 - Nov. 10, 2010, 6:51 a.m.
I certainly would not recommend leaving your account unprotected - but you would need to remove the current one if you wished to replace it with another mobile app download.
Have you seen the new dial-in authenticator that just got launched today? Might be something to consider if you need some time before getting another mobile.
Information on the new Dial-in Authenticator can be found here.
Battle.net Dial-in Authenticator Now Available
http://us.battle.net/wow/en/blog/1113829#blog Battle.net Dial-in Authenticator FAQ
http://us.blizzard.com/support/article/35806