zer0: you don't have to have a kid to get a GC by marrying (a US citizen)...... all you need to do is
- get married and have a marriage certificate (you even don't need to have a ceremony, you can go to court and get married)
-live together for at least one year
-file your taxes as a couple (the couple must have at least 12K income together.... sajha experts correct me if I'm wrong), your spouse must have a steady job
-maintain your status
-your spouse should file a petition for permanent residency
-if you are a student, DSO of your school can help, you don't have to hire a lawyer


visit the uscis.gov for more information

hope it helps, good luck