Marc, there are a variety of supplicatory prayers one can use. As Deacon Lance has mentioned there are many Akathists.
Another possibility is the Moleben with a Canon. You can find the general form for Molebens at
http://www.orthodox.net/services/ and if you scroll down to Moleben he has services in pdf or html form, and also a chart for the appropriate moleben Gospel depending on the general intention or commemoration.
The "Moleben of Thanksgiving" can be used for any situation of giving thanks to God, and may be appropriate as a spiritual gift to your pastor.
Fr. John Whiteford also has a general form of the Moleben without a priest at
http://pages.prodigy.net/frjohnwhiteford/moleben.htm and many Canons and Akathists at
http://www.saintjonah.org/services/akathists.htm