How much RAM can I add to this machine?

How much RAM can I put in this machine"?

I suspect more that it has.

Here are the vitals:

Model Name: iMac

Model Identifier: iMac7,1

Processor Name: Intel Core 2 Duo

Processor Speed: 2 GHz

Number Of Processors: 1

Total Number Of Cores: 2

L2 Cache: 4 MB

Memory: 1 GB

Bus Speed: 800 MHz

Boot ROM Version: IM71.007A.B03

SMC Version (system): 1.20f4

Admittedly this is an old machine but I

have old expensive Adobe and other

software on it that I don’t want to upgrade.

So I have Photoshop and Illustrator that I

would be most often using from the CS4 suite.

And I have a 3d modeling/rendering/anamation

program as well.

One other tangential question: Can I get full

sized Mac US B keyboards and corded magic

mice from iFixit?

Thank you for time and attention;

JK