Welcome to a great addiction!
Your system is fine for running SH4.
You will need to patch it to 1.4.
See here for sites that have the patch...
http://forums.ubi.com/eve/forums/a/t...5/m/1901093545
There is plenty to read here on the forum. Lots of MODS to add to SH4. You are in for a great time. Start out by copying your brand new SH4 1.4 install to a safe folder and change the directory names. That way if you destroy your install due to adding mods you have an easy way to get going again.
Best of luck, ask questions and happy hunting!