I'm looking for an application somewhat like photo contact pro or ringo mobile with customisable ring tone and sms with mp3 support.

I've tried photo contact pro where its ringtone plays the whole mp3 but it doesn't have customisable sms tone.

Ringo on the other hand does support but it only plays a short clip of the whole mp3.

Any idea where I could find one that can play customise ring tones and sms in full mp3 rather than a clip of it like ringo does.

Try with ringo this:

When your mp3 tone is set, just copy the whole mp3 song to ringo's destination. Then you'll have the compete song.