If you are planning to get a desktop in near future then there is no point to buy expensive stuff for aging laptop.
Just get 6670 (Or whatever cheap GPU you can buy) and use it till then. Try to save as much as you can for desktop since better components in it would just be better for you. Make sure buying something expensive at the moment won't result in you not being able to afford an SSD later on for your build. Desktop is literally the best gaming machine you can find.