Re: external monitor for my laptop help needed.
You don't need to look out for much. Just buy a monitor and plug it in. Once it's in the monitor will (usually, almost always) support higher resolutions than the laptops screen even using the laptops actual gfx card. Obviously if you buy an old crappy monitor that will limit resolution.
Also, some gfx card can't support decent resolutions but you should be fine with an Aspire.
You don't need an external keyboard or mouse. It just runs like a second monitor and u can usually extend the desktop etc