Samsung Gravity 2 T469 / T404

i have a question. for those who have got samsung gravity 2 already, can any one tell me that do you need to have internet access on the phone to be able to use the telenav and also can you use your own mp3 ringtone as text messaging rintones. i had the gravity 1 which doesn't allow me to set my own ringtone for my text messaging..

please help..

thank you