1999 Volvo S70

Engine Mechanical problem
1999 Volvo S70 4 cyl Two Wheel Drive Automatic 197000 miles

My volvo S70 has had these issue for nearly a month now. Sometime when am driving, the engine check ligh come on and the ABS lights and also the llittle light illustrating the skid comes on. While this is happening, the arrow light comes on and begins to flash. Causing the car sound abit loud. When I come to a stop, the car moves real slow even after stepping on the gas peddle all the way down. The car only pick ups momentum whne the ABS break light go off. I have to down shift to third gear to avoid being hit by other motorists and I'd imagine this is not good on the transmission. Yesterday was my last stroll because now the check engine light is on and hasn't gone off and there now seems to be some noise coming from the bottom of the vehicle aroung the gear shift area. This noise sounds more like the exahust or muffller area under the vehicle. Here are the codes to help explain these symptoms:
The guy at advanced auto used his meter to read these codes. Please, if you can, provide me with some information or advise me on what I should do or atleast what do I need to fix first. I have avoided going to the VOLVO dealer for obvious rea$on$. Please help if you can. Thanks!
December 2, 2009.

Have CAT and exhaust checked codes show CAT performance low and exhaust leak. Also faults with transmission and ABS. CAT maybe cloged up causing loss of power and the noise. That may have cause other codes to set. Anyway you need help so if no dealer find independent shop.

Dec 2, 2009.
Ok, would you recommend firestone or meineke to check CAT and exhaust? And if CAT is clogged up, can it be unclogged or may need replacing?

FYI~~~Just got an email from another board saying PO722 code is faulty speed sensor thus causing the ABS light as well as loss of power. I should also mention that, when the ABS light up togther with the engine check light with the arrow flashing all at the same time, the speedometer gets disable and can't really tell my speed when driving. Thanks.

Dec 2, 2009.