I have a Toshiba Laptop with AMD A10 Radeon HD 7660G. I have bought an external monitor with 2560 x 1440, but I can only get 1080. My windows box tells me that this is the maximum resolution I can get on the slider. I am connected via HDMI. Can I get more resolution for my external monitor? What is the maximum resolution for the AMD A10? If I can get more, how do I do this? Thanks.