How can I keep my maiden name as my middle name and married name as last name when getting my 10 year green card?

I've been married for 3 years. Got married in GA and have lived in NY. My marriage license application says my designated surname is my married name, but I haven't done anything about it and all of my legal documents say my first name&maiden name. 2 years ago USCIS told me that I can change my surname to married name by simply putting the name as I want on the i-751 form. But what about keeping my maiden name as my middle name as well as getting my husband's last name? I called USCIS&this lady said I have to get court order and include the receipt in my package. Some posts online say they just put the name they want on I-751. Do I have to go through court or not? Here it costs 250 to go through court, so I want to avoid if it's possible. Thank you in advance for your answers.