Iam german my wife is american how I can get residency in the US,that I can stay longer then 6 month ?

Since your wife is American you should apply for a conditional green card. The conditional green card is for noncitizens who married an American citizen. The conditional green card is for only 2 years of permanent residency status, while the regular green card gives 10 years. Within 3 months of the expiration of the the conditional green card, both you and your spouse must petition to have the conditional status removed. If your spouse refuses to do so there is the possibility of a waiver for that requirement. If you do not get the conditional status removed, the green card will expire and you can be deported.

Here:

http://www.uscis.gov/files/form/I-130instr.pdf

http://www.uscis.gov/files/form/I-130.pdf

your wife needs to file I30 form. that will immigrate u to america n then u can become us citizen. it takes 6-8 months period toprocess.