After you have the modem RPM installed you will need to run the following command as root:
hsfconfig this will setup your modem and link it to /dev/modem
As for the battery monitor you will have to recompile your kernel, if you feel you are ready for this you can follow the way I compiled my kernel found
here
I used the kernel config with .i686 on the end.
This is a Mini-Howto that explains the kernel compile question in detail
How-To
If you don't feel up to compiling a kernel just watch for your laptop battery light to go
orange then you know it is time to charge your battery.
HTH