String library will help you.
${var} Set Variable x: 647, y: 1174
${x} Fetch From Left ${var} , # now x should be "x: 674"
${x} Fetch From Right ${x} ${SPACE} # and now it should be "674"
${y} Fetch From Right ${var} y:${SPACE}
Or write a python function that does the same with regex for example.