Hi, thank for reviewing my add on. You select your base currency and the one you would like to convert to, then the browser will remember your selection and you do not have to select the currency every time.
For the way that display the value, I'm try not to fix to any format as everyone as different view on the format. So the current format is the very generic way of displaying it.
I feel sorry if my extension do not full fill what you need and I will try to improve it in the next update. Cheers!