xrandr --newmode 1360x768_60.00 84.75 1360 1432 1568 1776 768 771 781 798 -hsync +vsync
xrandr --addmode VGA1 1360x768_60.00
xrandr --output VGA1 --mode 1360x768_60.00



that reso is wrong of course and maybe output port or is it VGA? Anyway read more about xrandr, i think that is enough what you need. Its powerful tool.