This quest gave me trouble for a while - it basically comes down to having to avoid the AoE attack the PGL uses (Gutripper) so as to keep your HP at max at all times, so that you can survive Hundred Fists. When she goes all 'two hour' at about a quarter health left, this is where you have to keep spamming Shield Bash to stun her (it also does a fair amount of damage too). You'll probably just scrape across the line, but with a decent set of armour, sword and shield, and keeping your health up before she uses Hundred Fists, you should win the battle (battered and bruised though ).

Also I think Aldis was a douche for just standing there and just making snide comments about your 'progress'.