I have never tried it myself but with certain CDMA phones u can convert any audio into a ringer.
first you will have to download a video encrypting device such as EO Video and convert the movie u got into .wav format or .mp3 format. After that u can get a MIDI converter and it will convert the .wav/.mp3 into MIDI format which can be used for samsungs. For all these programs just go to www.downloads.com or go to the EO video website.
to get it onto the fone u can email it as an attachment and download/save it. Heres the tricky part: u gotta find where it was saved to, usually it saves to ur audio section but i really dont noe exact location (never used any Samsung A650 before) but once u find it u can apply as a ringtone.
it should work but i havent tried it out myself so good luck!