Mongodb increase part of object
===

I'm having problems updating a record. My document structure is something like this:

    "_id" : "1141825507009",
        "person" : [
            {
                "amount" : 25,
                "id" : "1141825507009"
            }
    ]

I want to increment person.amount by 3 where person.id is 1141825507009. That easy.
What about:

    Increment person.amount  by 3 if person.id exist.
    Add to person list with amount 3 and id 239something845 if person.id does not exist in list. 