Follow this link under the section "Get a Green Card While Outside the United States" and the other links it suggests. Should give you all the info you need.

http://www.uscis.gov/portal/site/usc...00082ca60aRCRD

The I485 is for if the applicant is already in the US with a valid status (Visitor, work visa) and you adjust need to adjust that status. This does not apply to your situation.