Array Subset will work with 2D arrays.
You'll need to set the row index, number of rows, column index and number of columns.
For the example you give, that might be something like "225, 15, 0, 2". If you leave any unwired, you'll get all of that thing (so you could also in the example above just wire "225, 15" and leave the column index/length unwired.
Well, in your VI I see the 2D array just before the Write Delimited Spreadsheet call, but there's no Array Subset connected to that wire.
If you'd like to write a second file with a subset, you can branch that wire, connect it to the Array Subset function, and wire the appropriate values.
Something like this, maybe?