Triple Monitors

Hello, I am trying to setup three monitors and can't get all three to work for the life of me. I will get straight to the point.

1st: I have a Samsung SyncMaster 2253BW (DVI port), which I would like to be my primary display (including Video Games)

2rd: I have an LG Plasma 42" Monitor (HDMI port), which I would like to be able to use sometimes as my Home Theater along with my MediaPortal front end.

3nd: I just got a free Dell 19" LCD (RGB port), which I would like to use as a simple secondary monitor, web and apps (including while gaming)

My rig is as follows:

Mainboard: Asus M4A78T-E
CPU: AMD Phenom II X3 720 (Socket AM3, Heka)
Memory: 4GB OCZ DDR3 PC3-8500F
GPU: 2x Sapphire Radeon HD 4850 1GB in Crossfire
PSU: 750w Crossair

Up until today I have been running both the 1st and 2nd monitors without any problems what-so-ever. I had both connected to one Video Card (DVI and HDMI). Though the 2rd monitor was connected to the video card through my Yamaha HDR-6130 Receiver (2x HDMI cords, monitor>receiver>video card). With this setup I could turn the receiver/monitor on and off without problems while the PC was running. I could play video games on my 1st monitor while someone else was running MediaPortal and watching an HD movie on the 2nd (2nd monitor is 15ft away in the living room).

Now throwing this third little LCD (3rd monitor) into the mix is proving to be a challenge. I just wanted another screen at my desk to look at webpages and possibly use some apps, while I am in a game or watching something on my primary display (1st monitor).

I would greatly appreciate directions on how I can setup these three displays to function as extended displays. Each just doing its own thing, no dual, triple gaming, nothing crazy like that just good old fashion real estate.

Regards,

RedFox