For the lost greencard, go to www.uscis.gov and fill out the online application for the lost green card(i forgot the form number, but go to the forms and efiling you'll find it), the fee is like $300 usd, you will be provided with the appointment date to the place that's near to your locale, this is for the biometric exams where they take your pics and fingerprints, make sure you take your photo IDs after that you are all done, it will take like two weeks to get the new greencard that would be mailed to you.