Powershell - Import File based on Day

I have a powershell script, that is going to be used by patching, at the moment i am having a different script for each day, that is importing a file based on that day - IE Monday Tuesday etc.  I have 2 variables that i am having to change on each script.  So question is, is there a way i can get powershell to import the file name based on day ?

For example, if a Thu import the below

#Variables For File Names

$fileName = "C:\Patching\Schedule\WinA-Test_Thu.txt"
$csvname =  "C:\Patching\Schedule\WinA-Test_Thu.csv"