2002 front speaker replacement and change out the oem radio/cd

Hi ~

I have an '02 Prius with the AM/FM cassette above and the single CD down below (behind the door).

1 - I would like to change out the front door speakers to ones with tweeters.
Can anyone tell what size these speakers are?

2 - I am also considering replacing the radio - is it possible to put a radio/cd/mp3 player where the current single cd player is now?
Is there anything tricky about that, or is it straight forward?
I am not doing it - I would take it to an installer.

3 - any recommendations for installers in the San Francisco Bay Area (Berkeley)(Santa Rosa)?

I am not interested in the best of everything - just to upgrade a bit without spending too much.

Thank you for your time and assistance.