Hi,
Below are my details
date of birth : 27-04-1984
Place of birth : karaikudi , tamil nadu, INDIA
time of birth : 17:37

One astrologer here said that , i will face a lot of problems after 2011 december, as Shani is moving to 8th place from my rasi. Also libra is my lagna, so he is also moving into the lagna.
I am already having a lot of problems in my work. I am thinking of resigning the job and find a new one.
Is this the right time for me to do it or can i wait.
Is it like the situating will become worse after shani moves into my 8th house..? will shani's shift cause problems in my work..?

Shani is not a bad planet. He gives fruits if you work hard. ONLY if you work hard. 10th lord in sixth (Moon) will give you challenges in career, but you will be able to come out of it, quite easily, if you focus on the problem in hand. Shani's shift to Thula this year end will bring good luck to you.

Shani in first house, even though exalted, retro, may cause some confusions with respect to everything in your life (just like you have doubts about your career). Exalted Sun, Venus, Merc in 7th house will get you a very good, intelligent  spouse.

Thank you ratchetandclank.
So can i expect the situation to become better after shani's shift..?
Also if i resign my job now, how far is it easy/difficult to get another job immediately..?
Sorry to ask this again, as i dont have any financial support from anyone else, hence without a job it will be difficult to manage my life.

Also i am having ulcer, BP due to this hard life. I want a peaceful life. Is it possible.?
Will i be able to live peacefully after shani's shift to 8th place in my rasi..?

Shani is moving to 8th house from Moon. But it is entering your lagna, and it is in the same position in your Natal chart. Sa in your ashtakavarga chart has decent strength, so you should have better life.

Basic rule about changing job: Get a job, then resign the existing job.