回复：请问LG是公民, LP是H1B, 申请婚姻绿卡是否需要请律师办,非常感

It is really simple for this case. Just do some reading on uscis website
http://www.uscis.gov/graphics/formsfee/forms/i-485.htm
and follow the instruction to fill out the forms.
And I do not think hiring a lawyer gives you any advantage. :-) unless you do not mind wasting another thousand dollar.

Also check out this forum and there are lots of useful information on this topic.
http://www.immigrationportal.com/forumdisplay.php?f=39

Good luck!