First, take a look at this thread and the scripted find examples in it:Scripted Find Examples
It shows a number of ways to use dates to perform a find.
Here's a set field step to use in such a script that will find all records dated in the same month as the date entered/selected in a global date field:
Set Field [YourTable::YourDateField ; Month ( Globals::gSearchDate ) & "/" & Year ( Globals::gSearchDate ) ]
with the date example from your post, this enters: 1/2012 as the search criteria and should find all records dated in the Month of January, 2012.
Assuming that the first month of the first quarter of your fiscal year is January, the following calculation could be used with Set FIeld to enter a date range for finding all records of the same quarter:
Let ( [ D = Globals::gSearchDate ;
Y = Year ( D ) ;
Q = Ceiling ( Month ( D ) / 4 ) ; //returns a value of 1, 2 ,3 or 4 for the quarter
M1 = Q * 3 - 2 ;
M2 = M1 + 3
Date ( M1 ; 1 ; Y ) & "..." & Date ( M2 ; 0 ; Y )
For your example date, this will produce the criteria: 1/1/2012...3/31/2012
Note that using 0 for the day parameter in the Date function returns the date for the last day of the preceding month.