sprint legacy plan and phone upgrade options

[sebo]

been out of the scoop for a while so...

I have an old plan that is 300 anytime minutes with unlimited incoming minutes, data and sms. after fees and taxes it's around $45~ a month.

i'm using a touch pro 2 which i'd like to upgrade to something a little newer.

anyone know if i can upgrade to an android phone keeping my currently plan? i don't care about 4G since it's not available in my area. i don't mind paying an additional $10/mo if i have to but i have the feeling i have to upgrade to a $60-70+ "everything" plan?

i know with sero plans you have the ability to upgrade to an android/3G phone for $10 more.. wonder if this applies to legacy plans too?