Need some information on what is next in line for chemo

Hi:
My father has NSCLC stage IIIB, inoperable. He was diagnosed in July 2007, and is doing well. The cancer has remained in his lungs, knock on wood.

My father started with chemo on August with Taxol and Cisplatin. He then went on Tarceva, and then Alimta. He could not tolerate the Tarceva (it caused extreme eye irritation and extreme rash). He had good results with Alimta, but had some progression so was switched to Navelbine, with success. He then took a break and was placed on Gemzar.

He is concerned that the Gemzar is not working since he has some sharp pain in his lungs and shoulder(which he had before the Gemzar). Also has some numbness in the feet, which I understand is a normal side effect. Also, his white blood count has been low on two occasions, which has caused him to not be able to get chemo a couple times, which prolongs the CT scan to see if the Gemzar is working.

My questions:
1.) Any experience with the Gemzar or any other chemo causing some sharp chest pain that comes and goes irregularly?
2.) What other drugs are there that he can get after the Gemzar?
Any help or suggestions are greatly appreciated.

Thanks!