* Example of one line of data, in variable T1. In your macro the Text File Process will populate the text variable, rather than the Set String command.
Variable Set String %T1% " X:1701 Y:580"
* Set integer to position of "X:" within the data
Variable Set Integer %N1% from Position of Text in Variable %T1%
* Bump position up by 2 characters so N1 is pointing to the first digit instead of to "X:"
Variable Modify Integer: %N1% = %N1% + 2
* What Cory said -- move four digits from the data to another variable
Variable Modify String: Copy Part of %T1% to %T2% [starting position N1, number of digits 4]
* Display the extracted digits to verify the extraction is working properly
Text Box Display: %T2%
Of course in your actual macro, you would move the extracted digits to the array instead of Text Box Display.