I'm a first day miner and my software is mining about 140-160 MH/s. Is this a good amount? (i'm kinda noob at this thing)

I have windows 8.1 and nvidia gtx 670


I have intel i5 4590U CPU at 3.30 GHz and 6 GB RAM

Any suggestions if i can do better?

P.S electricity costs 10 cents per kilowatt hour