Ron,
You will definately need a minimum of 100psi & 2 x 3 stage vacs if you want to start up in carpet cleaning. There are plenty of good second hand machines out there. The most important thing for you to do is get some training, as this will give you a feel for the business and if it is right for you, plus you will get a basic understanding of machines, fibres, and problems you may encounter etc.
Also looking at your picture you may want to leave it for another 16 years as some of the carpet wands may be a bit too high for you

Good luck.
Derek