Car seat help?!

M.
Okay, so I have two kids. My little boy is 3 and is front facing in a Graco Nautilus LX 65 3-in-1 and I'm looking for aconvertible car seat for my 8 month old that will fit rear-facing in my 2010 Mazda 3 without causing me to have my knees to the dashboard like usual. Any suggestions are welcome! thank you in advanced!!