You can go to the border and apply for a new work permit. I was told by an immigration officer that sometimes the officers at the border don't like this and they have the power to refuse entry. However some people are doing it without a problem. It's a risk that you may consider taking, try to find people who have done it. The other option is to go to an immigration office and tell them your case. They'll ask you if you can survive (money wise) until you get your work permit. They'll ask you if you have anyone who can lend you money, even in your home country. You may have to show them proof that you could not survive while you are waiting for the new work permit.
You may also ask for an extension on the first work permit for a maximum of two years if it is low skilled.
To find a new job, I suggest you visit
http://www.jobbank.gc.ca/ Many of the people here are getting work permits for employees and may already have an LMO where they can add your name to it.
There are occupations under pressure where the LMO is somewhat expedited. Find the list here
http://www.hrsdc.gc.ca/en/workplaceskills/foreign_workers/occunderpres.shtml I also suggest that you find a semi skilled or skilled job (NOC 0, A or B) so that after two years you can apply for the new CEC (canadian experience class) and become a resident.
You may remain in Canada until the end of the visa (2009) even without a job. when you find the other job and get a work permit, you'll be able to stay for the duration of the work permit. If you need to come in and out of the country then you may apply for a visa in buffalo.
God bless you!