VS 2010 - Convert Latitude / Longitude Into Values In Decimal Degrees

Create a function named DecimalDegrees to refactor the code that converts a latitude or longitude into a value in decimal degrees. (This function will be used inside the functions ValueOf and Distance.)
Task 2a: Write the code for the function DecimalDegrees with an input parameter for DegreeString as type string, and returns the value as type Double.

Here is my code for the function part
Private Function DecimalDegrees(ByVal DegreeString As String, ByVal degrees As Double, ByVal minutes As Double,
ByVal seconds As Double, ByVal ID As Integer) As Double

I am having difficulties with the 2nd part which is I believe to take the code for the calc1 and calc2 buttons and somehow get it to convert to decimal degrees by the function I have created. The buttons would then be removed as the code would automatically take the latitude and longitude and convert the degrees, minutes and seconds into a decimal.

Here is the code for the current buttons:
Dim StartPtr, StopPtr As Integer
'To Replace Calculator 1 Button
'Convert degrees before passing argument - Latitude
StartPtr = 0
[Code] .....