Well if you have the CSR pedals (these:
http://eu.fanatec.com/Pedals/CSR%20Pedals%20EU ) then you can't use them stand alone, but then again those are potentionmeter pedals just like the ones that come with the T500 (which are decent pedals mind you), so you might as well use the Thrustmaster pedals instead. If you have the CSR-Elite pedals or better, then you have a loadcell brake pedal, but then you also have the option of running them as USB standalone pedals so there's that issue solved for you.
The shifters are properitary, no Fanatec wheel = no shifter. The upcoming shifter will most likely be the first to change that though. There MIGHT exist a Fanatec shifter adapter, like the one Leo Bodnar makes for the Logitech shifter, but I haven't seen one and I honestly don't think the Fanatec shifters are popular enough to warrant someone making an adapter. If you don't want to loose the shifters nor buy a new one (the Thrustmaster TH8 RS shifter knocks those Fanatec shifters out of the water), then you will need to upgrade to a better Fanatec wheel, but that will run you 600+ dollars like you said you didn't wanna spend.
If you ask me then I'd say get the Thrustmaster shifter (or wait for the new Fanatec one, but I suspect it will be more expensive), you won't regret it cos it makes your current shifter seem like toys.
Also, do you really need 1080 degrees rotation? I rarely find myself using the full 900 on my GT3 wheel, can't see the use of the extra rotation, but that's me.
[/quote
I have the csr elite pedals i love them. My idea is to run my csr pedals by usb stand alone and get a g27 shifter and get the adapter to run that stand alone.