I can help you solve the first problem.
It is probably the refresh rate of the monitor that limits your resolution.
You can edit the file /etc/X11/XF86Config-4.
Find 'Section "Monitor"'
You need to edit:
HorizSync 30.0 - 70.0
VertRefresh 50 - 90
These are my settings. You may be able to use higher or lower. Beware that a too high refresh rate and HorizSync could fry your monitor.
Try what works for you.
Backup the file before you save your changes!
Then you need to restart X. Logout and press Ctr-Alt-Backspace.