Buying a second monitor to use as an auxiliary

[Melt My GPU]

Hey there, to keep things quick I'll cut to the chase;

 

• Current monitor is an LG Flatron IPS235 (1080P IPS) that I got when I first built my rig and I don't think it's available anymore
• I desire a second monitor to use so I can have games/movies etc on one in full screen and have all my other jargon/fb convos on the other so I don't have to keep minimizing and maximising to switch
• Indecisive to whether or not I get 2 new monitors so the image is exactly the same or just buy another one and hope it doesn't look too different
• Not too keen on spending more than approx $700 AUD if I'm buying 2 new ones but if it's well worth it I can spend more
• No idea what's actually classified as good monitors or not
• If I purchase one should I spend more to get a higher resolution display and if so how does feel to use multiple monitors of differing resolutions?

As previously stated one of the monitors (either the new one or the existing if I buy one, whichever's 'worse') will be used as the auxiliary so I will only be gaming on one of them. If it matters I run a GTX 670.

 

Thanks for your time and hopefully you can help me out

[WoodenMarker]

Close enough? http://au.pcpartpicker.com/part/lg-monitor-23mp55hqp

[m_tieu]

I would try to get another one with the same size and resolution so Windows will remain the same size moving from one monitor to another. Getting another ips panel would be a good idea as well since you won't be looking at them both strait on simultaneously and colour shifting looks really bad when looking from one end of your set up to another.