Unfortunately, there is not a cheap good or ideal way to do this.
The graphics card is a key integrated part of the logic board on the MacBook Pro, there really is no separation of it from it to do an upgrade, short of replacing the entire motherboard, and even then you would be limited to what was available at the time for that generation of MacBook Pro.
See that orange highlighted square, thats the NVidia GeForce pictured below:
Honestly, the Matrox route is probably the most affordable workable solution to this problem.
This MacBook Pro also lacks an ExpressCard/34 slot or Thunderbolt so you really can't go the route of an external graphics card. And even if you could you would be talking over $500 USD just to get the external PCI express chassis, for example Magma's ExpressBox 1 starts at $829 for just one external PCI Express slot, you would still need to spend another ~ $200 to buy a mac compatible graphics card.
Your last option is to maybe reevaluate if this MacBook Pro is the right machine for your needs. Would a newer model MacBook Pro with Thunderbolt solve this problem, maybe maybe not. If you don't have two Thunderbolt Displays, you are kind of still out of luck hooking up dual displays to even a Thunderbolt MacBook Pro, with out the need for expensive external adapters.
Would an iMac, Mac Mini, or Mac Pro better suit your computing needs, complimented with a basic MacBook Air or iPad of some kind for your mobility needs.
Our development team all use Macs. I have personally tried to use VNC both with Apples built in and premium Apple Remote Desktop ($79.99), as well as Jolly's Fast VNC. I had a Mac Pro tower at work and really needed the remote capability, and was able to work reasonably well with Apple Remote Desktop, but when my tower came off lease I went with a Laptop, because the lag and poor display quality were just too annoying. I found that I needed to degrade the display quality in order to keep the performance reasonable, which meant a blurry display. Overall I found it frustrating and avoid remote access, but it does work, although I would strongly recommend buying Apple Remote Desktop to get the full screen capability. Jolly's was fast but at the time had some bugs that resulted in a corrupt screen sometimes. That was over a year ago, the new version may be better.
There are other developers I work with who think that the VNC solution works just fine for them, so I think it depends a lot on how fussy you are about responsiveness (I am fussy).
If your previous experience with remote access involves Microsoft's Remote Display Protocol (RDP) then you will be very disappointed with VNC. The RDP technology is superior in both display quality and performance. One of the few things I really miss from the Microsoft world.
In short, I'd recommend moving to an Apple laptop and then running your Windows virtually. I started with a mini originally, and just ended up moving to a laptop eventually.
Best Answer
Easy enough to do with Microsoft Remote Desktop, available for free on the app store.
If you plug an Ethernet cable between the two computers they should negotiate a network connection and you will get gigabit speeds.
Note that this is different for what you can do with an iMac where you plug a Display Port video cable into the iMac and use the iMac as just a display. To the best of my knowledge Apple does not support this on its portables, only the iMacs so you are limited to whatever Microsoft Remote Desktop will support using RDP.
It is possible that there are other apps that might do a better job. VNC is a 3rd party open source remote control app, similar to Microsoft Remote Desktop except you will have to install it on both machines. There might be others that give you better performance but the MS app and a VLC app would be the place to start.