A engine head gasket to change

1992 chevy Lumina APV , 152 249 km[/b][/i]..

My question is??

How much would it cost me ( time & parts )
to change an engine head gasket ?
And
if i would like to change it myself?
Could you send me a diagram explaining me exactly how it should be done?

Please send me these informations right away!

Thank you and have a great day!

Stephane Paradis

[email protected]