[Power Steering fluid looks bad!!]

I decided to change out some PS fluid today , I had not touched it since buying the car, its 07 corolla. Well , the fluid I removed was light brown though clear not cloudy. I could see many various size dark particles in the fluid. The PS works fine, the only thing I can think of is a rotting seal or rubber hose. I dont know if I should check into this further or just leave it. Any ideas on what to check. Thanks

[07 corolla auto trans service]

I went to PEP Boys to get trans fluid and they said I can only get it from Toyota, is that true??

Can I drain it myself? I dont see any external filters to change. Looks like I can drain about 4 qt per the manual. Is that enough or is a dealer flush worth doing I am sure its very costly. I have about 60k on the car but would like to do the atf.

[07 auto trans service]

I have about 40k on my car and I would like to change the trans fluid. Should I buy toyota atf or can I use a synthetic. Not having any problems.

[How to reset the oil change/Maint Req light]

I have a 2007 corolla and want to be able to reset this light without going through an oil change . Is it set to come on at 3k mile intervals , how is it triggered? thank you ( I promise I will be changing my oil regularly)