unable to fully install elementary os Luna on imac 11.1(late 2009)

I have tried to install Elementary os Luna(64bit) on my imac 11.1(late 2009 , processor intel i5, videocard ATI radeon HD 4850). At this moment it working but not very good, I will give you a summery of my installation process and my problems. First off I made a bootable usb using VMware and Startup Disk Creator, other methods did not work. When I boot up the Eos usb I get a grub , I need to hoover over install Eos en press the e-key to edit the code. I write down $ nomodeset xforcevesa and press F10 to boot. Now I am able to install Eos, I select my partition and make it ext4. At the and of the installation it ask me to reboot , I press on reboot and the first time I get just a black screen ,so I reboot again and get the Grub with Eos and Eos recovery mode. I need to hoover over Eos again and press the e-key to edit. I again write down $ nomodeset xforcevesa and press F10 to boot . It does no boot up in GUI -mode but in single cmd-mode(terminal). It ask me for my username and my password,which I gave.Then I write $ startx and get the error 'no screens found'. I looked around and found on the ubuntuforums that it had something to do with having Hybridgraphics. I used the info on this site (https://wiki.ubuntu.com/X/Config/HybridGraphics) and wrote the following down.

$ sudo apt-get update

$ sudo apt-get upgrade

$ sudo apt-get dist-upgrade

$ sudo apt-get install linux-generic-lts-trusty (raring and saucy did not work)

$ sudo apt-get install xserver-xorg-lts-trusty (raring and saucy did not work)

$ sudo apt-get install fglrx-experimental-13

$ sudo apt-get install fglrx-pxpress

$ sudo reboot

Now it boots up in GUi-mode but I have an invisible mouse the first 2 minutes. When mouse pointer becomes visible it's not a normal pointer but a X-pointer, I open some apps and discover dat the apps have no windows borders.I look around again and find it has probably something to do with fglrx . I open terminal and write down $ sudo apt-get purge fglrx* , and reboot the system. The first time I reboot I get a black screen so I reboot again and get the Grub again with the choice between Eos and Eos recovery. I need to hoover over Eos again and press the e-key to edit, I write down $ nomodeset xforcevesa , and press F10 to boot. Now it's boots up with a normal mouse cursor and I have window borders. I install firefox and the flash plug-in and discover that video is not working good, on YouTube don't have 30 frames/s more like 10 frames a seconds which make makes watching video inpossible. I look on the web again and find on the UbuntoForums that I need to install the right driver. I go the AMD site to download Catalyst legacy 13.1 ( the last version that supports my videocard ). I run the download in the terminal, the program pops-up , I try to install but it gave me the error 'more tools required' . My second attempt was using the ppa:makson96/fglrx , it did not work, it crasht Eos , so I need to repeat the process all over again.

To sum up: 1, Eos boots up only ones every two times and when it does I need to manually force $ nomodeset xforcevesa. 2, I'm not able to watch any video because off the slow response .

So here is what I need help with. All help is much appreciated.

P.S.

Sorry for my bad English it's not my native language.