All U need is Soundforge or any other sound editor. Export ur ringtone out to ur hdd. Then Import to soundforge and do the editing. Del the rest of the part that you do not need. Then, render out as what extension u want. Need not to render as wav, it will only make the file bigger and if the original file is not a wav, by making to wav is no no situation. weird quality.
Im not a Pro SF as Im using other software like Samplitude, Cubase and Protools. Drop me a pm if u require some help.
You may wan to find from download.com. Might have more source of freeware. if not, try some trial ware.
Maybe you can try this freeware, Audacity, the free audio editor.
Excerpts from their website :-
This is a list of features in Audacity, the free audio editor. For more information on how to use these features, go to the help pages.
Audacity can record live audio through a microphone or mixer, or digitize recordings from cassette tapes, vinyl records, or minidiscs. With some sound cards, it can also capture streaming audio.
Record from microphone, line input, or other sources.
Dub over existing tracks to create multi-track recordings.
Record up to 16 channels at once (requires multi-channel hardware).
Level meters can monitor volume levels before, during, and after recording.
Import and Export
Import sound files, edit them, and combine them with other files or new recordings. Export your recordings in several common file formats.
Import and export WAV, AIFF, AU, and Ogg Vorbis files.
Import MPEG audio (including MP2 and MP3 files) with libmad.
Export MP3s with the optional LAME encoder library.
Create WAV or AIFF files suitable for burning to CD.
Import and export all file formats supported by libsndfile.
Open raw (headerless) audio files using the Import Raw command.
Note: Audacity does not currently support WMA, AAC, or most other proprietary or restricted file formats.
Easy editing with Cut, Copy, Paste, and Delete.
Use unlimited Undo (and Redo) to go back any number of steps.
Very fast editing of large files.
Edit and mix an unlimited number of tracks.
Use the Drawing tool to alter individual sample points.
Fade the volume up or down smoothly with the Envelope tool.
Change the pitch without altering the tempo, or vice-versa.
Remove static, hiss, hum, or other constant background noises.
Alter frequencies with Equalization, FFT Filter, and Bass Boost effects.
Adjust volumes with Compressor, Amplify, and Normalize effects.
Other built-in effects include:
Record and edit 16-bit, 24-bit, and 32-bit (floating point) samples.
Record at up to 96 KHz.
Sample rates and formats are converted using high-quality resampling and dithering.
Mix tracks with different sample rates or formats, and Audacity will convert them automatically in realtime.
Add new effects with LADSPA plugins.
Audacity includes some sample plugins by Steve Harris.
Load VST plugins for Windows and Mac, with the optional VST Enabler.
Write new effects with the built-in Nyquist programming language.
Spectrogram mode for visualizing frequencies.
Plot Spectrum command for detailed frequency analysis.
Free and Cross-Platform
Licensed under the GNU General Public License (GPL).
Runs on Mac OS X, Windows, and GNU/Linux. ""