How can I code a Macro in Excel to search in a preset directory and open a certain Adobe Acrobat .pdf file ?

Example: If cell L1 has a date of 5-Jan, I want it to open a pdf file called 5-Jan.pdf, which i can do with the following:

Sub Payslip()
MyPath = "C:\Program Files (x86)\Adobe\Reader 9.0\Reader\AcroRd32.exe"
MyFile = "C:\Users\Dads\Documents\Payslips\2012\5 Jan.pdf"
Shell MyPath & " " & MyFile, vbNormalFocus
End Sub

But when the date in cell L1 changes this is no good.
I want it to open pdf file based on the value of cell L1.
Any help appreciated Thanks.