Hey there,
It'd be nice and helpful if you could tell us where you're from so other members can relate and help you
But I'll assume your from the US for now,
If I have heard correctly, Pentax has official repairs in the United States from CRIS and many have had good experiences with them. Sadly, I don't live in N. America at the moment so I cannot give you specific info.
Here's their website and you can get a quote on the lens,
Camera Repair by CRIS Camera Services - Pentax Camera Repair EDIT
Just checked your profile, and you're from the Philippines.
I'm sure people will have experience getting their gear fixed up in Singapore or Japan.
Check out Pentax's service network
http://www.ricoh-imaging.co.jp/english/support/repair_entry-asia.html
They've got a listing for the Philippines,
PHILIPPINES
Super East Asia Enterprises, Inc.
Ground Floor, Philflex Bldg. 407 Dasmarinas Street., Sta. Cruz Manila
(63)-241-3851 / 242-2647
Cheers from Taiwan
Hope this helped,
Steve