Anyway, below you will find the guide that worked for me.
IMPORTANT NOTE: Please for the love of god, take a complete backup of your important data. If possible create a spare partion of your working OS X Lion and then clone it. Please don't ask me how to clone your Mac. I'm sure you will be able to find a lot of tutorials on the internet. However for cloning I personally prefer CCC which stands for 'Carbon Copy Cloner'
I have also attached the files that worked for me, which you can download below:
EDIT: RE-UPLOADED THE FILE BELOW, THERE WAS A KEXT MISSING IN EARLIER ZIP FILE... YOU CAN DOWNLOAD THE NEW ATTACHMENT BELOW:
ATIRadeonHD4350KextsNEW_AlexMathayes_.zip 1.48MB 1488 downloads
NOW let's begin.
1. Shutdown and Install the Graphics Card ATI Radeon HD4350 and boot
NOTE: Boot with normal mode. If the normal mode doesn't work then boot into safe mode. And if safe mode also doesn't work, then remove the card and continue with the steps below. I however, did not have to boot in safe mode, I just booted in normal mode with my Graphics card already installed.
2. Open the 'EVOenabler and ATY_init' folder, Open 'Applications' folder in a seperate window. Select both the files in 'EVOenabler and ATY_init' folder and drag them over to 'Kext Utility' found in the 'Applications' folder in order to install them automatically with permissions also being repaired automatically.
3. Open 'ATI4350' folder and copy paste the file to 'Extra/Extensions' folder.
4. Open the 'Controllers' folder and again 'Applications' folder opened in a seperate window, select all the files from 'Controllers' folder and drag them over to 'Kext Utility' in order to install them automatically with permissions also being repaired automatically.
5. Open 'Kext utility' again by double clicking it, type your password and let it repair the permissions automatically.
NOTE: It's better to run the 'Kext Utility' last time just to be on a safe side that the permissions gets repaired. Although you are repairing the permissions each time you drag the kexts to 'Kext Utility'.
6. Restart and at the bootloader, boot with -v. You should see ATI4600Controller might not load (Thats normal), you should also see ATY_Init with card 0x- and random few numbers, this indicates that the installation was successfull.
VERY IMPORTANT NOTE: I had a very tough time installing this card and had almost given up. But I beleive in 'try, try... untill you succeed' hence in case the above procedure does not work and after installing the card you get a BLANK GREY SCREEN with just a big arrow, you can then perform the extra step 7 (Which I had to do since, I was getting a BLANK GREY SCREEN with a big mouse pointer).
7. (THIS STEP IS ONLY FOR PEOPLE WHO GET A BLANK GREY SCREEN) When performing the 2nd Step from above, Open the 'EVOenabler and ATY_init' folder and ONLY SELECT 'ATY_Init.kext' and drag it over 'Kext Utility' in order to install it. Then you can continue with the Step 3.
ATI_Radeon_HD4350.jpg 58.98KB 779 downloads
Thats it, your Graphics card should be recognized as 'ATI Radeon HD 4600' when you open the System Information. Hope the instructions were easy to follow. I have only tested this procedure with the DVI Cable connected hence, I would not be able to comment on the VGA method, I'm sorry. ALL THE VERY BEST.