Currently Being ModeratedDec 7, 2012 4:25 AM (in response to iPhoneRockstar)
You need to assign the ringtone either as the default ringtone for all calls or, specifically, for an individual person.
If the former:
1) Go to Settings.
2) Go to Sounds.
3) Go to Ringtone - on selecting you'll be able to scroll through to your new purchase.
4) Once ticked this is your default ringtone for all calls.
If the latter:
1) Open Contacts
2) Select contact you wish to assign ringtone to.
3) Click 'Edit' (top right of screen)
4) Scroll down to Ringtone - select and repeat process stated in first section above (i.e. scroll and select tone).
5) Click 'Done' (top right of screen)
Hope this helps.