The DB zip was very helpful. My suggestion would be to turn your concept upside down from the date point-of-view. Dates are a little tricky for all of us.
The design currently assumes a 5th week. My guess is that there is not always a 5th week. Lets look at this from a different way.
What day of the week do you consider the week to be for your Church's accounting purposes?
For example: The Catholic have Friday evening mass that counts through Sunday, so collections are based on Friday through Sunday. Another church has Saturday morning services, while others have Sunday morning only.
First, determine what your church considers its collection period. Don't assume it is follows the calendar.
Once this is known, start with a table that contains the Collection Period Begin Date. For a beginner, it might be worth just adding this to the table from now to 2019.
From here, let the computer run a formula to determine if this is week 1, 2, 3, 4, 5.
This would change the form to open on the current year and current month.
From there, the user can change the year / month - the computer creates a dynamic list box that has 1 to 4 or 1 to 5 depending on that combination.
To do this quickly, Excel was used to list all of the Sunday dates since 1/6/2013
Often in accounting, knowing the week 1-52 is useful - that was also added.
Next is the week in the month (1..5) this was accomplished with the formula:
=LOOKUP(7+DAY(A2)-WEEKDAY($A2,2),{0,8,15,22,29},{1,2,3,4,5})
Knowing the numeric month number can be useful in dropdown box
in excel the formula is =MONTH(A2) and for year =YEAR(A2)
These were pulled down for 18 months then imported int Access
Now the DB is starting with a universal table for the time periods needed.
This allows more flexibility for looking up information and having it ready cross referenced.
So, after importing the table - I built a little object in your Report form to give you some ideas.
It will open with a list box for the Sundays. The list box will change based on the controls. The dates with the weeks 1..5 will display. Choose one - to automatically fill in a text box.
If you use this table as the basis for all your reports, it might give a standard frame of reference.
It might be enough to give you some ideas and get you started.
I am going to use this same weekly count on a government permit accounting form.
Be sure and look at the Sample Databases found on this site's forum.
There are some good example that might be useful for your assignment.