A Greek asks for advice about immigration issues to Canada, and we get American's talking about the USA and its political issues instead.
Once again, http://www.cic.gc.ca/english/index.asp
is the only government website to use for information on immigration to Canada. I'm a Canadian born and raised who married a Danish citizen. We went through the application process for Landed Immigrant status a decade ago for my wife. It can be frustrating and slow.
A few hints...
Many immigration consulting agencies are complete scams. Be very careful handing money over to these individuals as they have zero additional pull. The government immigration forms are designed so that any high school graduate can fill them in. Get a Skype account if necessary and fill in the forms yourself, and phone Immigration Canada's help line when you have questions. You will save yourself thousands of dollars. If you feel you must use an immigration consultant get a long reference list and check them all carefully. Many of these agencies prey on vulnerable people with little options. Use them only as a last possible option.
Have your sister develop a positive relationship with her Federal Government Member of Parliament. The staff in these offices can work miracles when necessary to speed things up. It doesn't matter what party the MP belongs to. The MP is your sister's link to the Federal government.
Start taking Rosetta Stone or similar English skills training ASAP. Having a strong working knowledge of English will make your interview with government immigration staff go much easier and will greatly help in your job search.
North of Edmonton in the town of Fort McMurray, things are absolutely booming with Oil Sands production. However this once tiny town is struggling to keep up with the mass influx of new resident oil workers and inflation has hit the area badly. If you get a work offer in this area ensure that you have accommodation plans included for the first couple of months as finding a place to live here is very difficult.
Getting a mortgage to buy a house will be tough until you have several years with a job. Without a reasonable Canadian work history, getting a home mortgage can be very tricky unless you are including a large down payment at time of purchase. Be prepared to rent for a while unless you can make a cash purchase of a property.
Best of luck with your move. The immigration process can be a slow pain in the @ss but once it is finished you will have a chance to live in the largest by geography, free country in the world.