How much power is too much to draw from my car

[NSWESP]

I am fitting out my car at the moment and was wondering how much power is too much to draw out from it.

What i already have being powered is:

3 Socket 12v Adapter gives me 3 sockets from the one stock on in my dash. That powers:
1x Uniden RH96
1x Uniden 500SX RM UHF Radio
1x LED Dash Flasher or handheld Scanner depending what i need

In the trunk i have a 2 socket adapter with the Uniden 396T thats hooked up to the RH96, what i want to know is it too much to hook up a 12v -> 240v power inverter. Would this overload my 2008 VW Golf hatchback?

[N_Jay]

What is it labeled (check owners manual) at?
What is it fused at?
Either use the label, or 1/2 to 3/4 the fuse rating is usually just fine.