Power steering question ??????

[AngeloViveros]

Hi all, like 2-3 months ago i check my steering fluid and it was low, just re fill it with regular p/s fluid, i use the whole small regular bottle that was available on the gas station, now a coupl days ago, the same thing, since the first time i did notice some kind of leak i think is the hoses.
Now i just did my research un luckily i find out that bimmers use ATF insteed of p/s fluid, this time when i check the fluid is kind of dark brown, so am not sure if it just the age (almost 200.000 miles) or my p/s fluid add.

the questions
-how bad is for the system my add of regular fluid
-how do i flush it, i try pelican parts or others and cant find a DIY or one that has pictures (english is my second language) kind of hard undestand all the terminologies.
- i read that p/s leaks are mostly cause of the clampand not the hoses, and everybody said to get a decent one, any ideas of wich ones are the best to do that, if you can add a bmw part #, or a link please


thank you guys i really apreciate the help