Monitor Upgrade/GFX Upgrade!?

Hey so I am thinking about getting rid of my old 19'' secondary monitor, using my ASUS 24'' LED 1080P 2MS monitor as my secondary and buying this monitor as my main gaming monitor, the BenQ XL2420T Black-Red 24" http://www.newegg.com/Product/Produc...82E16824014270

I was told this is a great gaming monitor and would be used as my main monitor for gaming, I was also reading another post and Maximum PC was saying it's one of the best gaming monitors today and it was constructed by Counter-Strike players, which was one of my favorite games of all-time! I currently have a GTX 670 TOP from ASUS and was wondering if I should get another one for SLi, save some money and get a GTX 660 Ti, since they are coming out as stated by some information I was reading today on another PC website, and sell my current 670 and get GTX 660 Ti SLi or just get another 670 and SLi? Probably be a lot easier to just get another 670.

In the end it'd be easier but I'd be saving a couple hundred bucks by getting the GTX 660 Ti SLi config rather then another 670, but yeah from the specs I am reading about the GTX 660 Ti, they seam pretty darn good for $299, if that's what they are going to sell for. Also the ASUS GTX 670 TOP that I have has given me some issues with the power target and the GPU Tweak and all of that so I am thinking about doing something with my current GFX setup, it is a good card just sometimes unstable. Should I wait for the GTX 660 Ti to be released? Sell my ASUS GTX 670 Top and get another card? The GTX 680 Classified or Lightning or maybe even the HD 7970 Toxic GHz ed?

My computer specs are listed below:

i5 2500K @ 4.5GHz + Cooler Master H80 Liquid Cooling Unit
ASUS GTX 670 DCII TOP
Gigabyte Z68X UD3H-B3
8GB G.Skill Ripjaws 1600
Corsair Force GS 180GB (Boot and Games)+ 750GB 7200 RPM Data Drive
ASUS Xonar DG 5.1
Corsair TX750W v2
Cooler Master HAF 912 Case
HAF 912 Gaming Case
Win 7 X64 Ultimate