If the accelerometer is currently functioning properly, in that the expected data stream is viewable in Hyperterminal, then one of the simplest methods would be to capture the data stream to a file.
Most terminal emulation software provides a method of file capture.
Do you have any experience in programming in .NET Framework? Or VB6?
If so, you could always write a small app which captures the data stream directly and formats as to your requirements.
More than like, the TI demo to which imranpatel is referring, was written in one of the many languages supported by the .NET Framework.
Another option would be to utilize MATLAB, which offers routines to process a data stream from directly from a COM port and write the results to a file.
The correct choice depends largely on which option you feel the most comfortable.
BigDog