The Laws of Prayer (77)

1. It is good to confess one’s sins in the blessing of “Shome’a Tefillah”, and to request one’s livelihood even if one is rich. (Mishne Berurah 119)

2. When one adds on and makes a request in one of the intermediate blessings, or even in “Shome’a Tefillah” when it is for a personal necessity (as opposed to a public necessity), some say that he should not lengthen his request too much. However, if one makes the request at the end of the Amidah even if it is before he has said “Yiheyu Leratzon”, everyone agrees that one may add at length. (ibid)