I would like to choke your doctor but that is a story for another day.
From where will you buy the machine? Most outlets, at least in the U.S., would sell you a ResMed S9 Autoset if you have a prescription for "CPAP".
Software is easy. Just download to your computer from ResMed's site -
http://www.resmed.com/int/assets/html/s ... ister.html
Your computer has enough capacity for the program.
The machine comes with an SD card which stores the data. You will need an SD card
reader to upload the data to your computer. SD card readers sell for less than $10.
Once you download some data and run a report you can find online a tutorial on using and interpreting ResScan reports. Maybe someone will now post the link. You can also get help from this forum members to interpret the reports. You will quickly begin to understand how your therapy is working and what needs to be tweaked - things like mask leak and pressure.
I hope you can get the AutoSet. The price on cpap.com is only 6% more than the Elite. That is $48. Spread over 5 years that is less than $10 per year. Well worth it IMO.
I think maybe your doctor thinks autos are to be set at pressure range 4 - 20 and then the machine finds the correct pressure. If so, I would agree with your doctor that this is a totally unsatisfactory therapy. But none of us set our autos this way. We set them at narrow ranges surrounding the straight CPAP setting. Then the machine adjusts nicely during the night to accommodate different sleeping positions, different levels of congestion, and other factors that vary during the night or night to night.