A) Wait a few days for the final Daryna
And - yes you will most likely get the broadcom chip to work under Daryna.
It would be nice if you had a separate home partition so you can keep your personal "belongings"
http://www.linuxmint.com/wiki/index.php ... _partition
As you are very new, read carefully once or twice before getting into action - and it does not matter if it's a dual boot or not - Gparted is very competent at changing the size of partitions. You should do a backup as there is always a small risk something goes wrong.
The list in Grub can be really long....
It's in a file /boot/grub/menu.lst and you can edit the file.
You have to use sudo for that. (which means you start, say, Gedit from the command line)
Make a copy first (actaully the simplest way is to "mark all" and copy/pate to a file youcreate on your desktop)