how to expand default size for sda2 partition

I installed OES 2 SP3 on SUSE 10 SP4. After installation I tried to extend default size (14.0 GB) of Linux system partition on sda1. SDA has a few hundreds GB of free space. I was trying to use both LVM and EVMS tools, but could not extend sda1. How to extend sda1 size to at least 100 GB during or after installation?

Thank you.

Vlad.