If you sponsor them under the federal system, it's not fast. You need to wait at least a year until you can prove income by tax return and then you can apply for them. The sponsor approval takes something like 29 months in Canada, see
http://www.cic.gc.ca/english/information/times/canada/process-in.asp#sponsorship and then gets sent to their visa office and takes another several months, see
http://www.cic.gc.ca/english/information/times/international/08-fc-parents.asp You could be looking at 5 years easy before they would get there. If they can get a visit visa, they could come and keep extending it but they would not be covered by health care and they would not be able to work.
You can see how much you have to make at
http://www.cic.gc.ca/english/information/applications/guides/5196E10.asp if you scrool down to table 4. For your little family of 3 + parents is 5 people so $45,662 a year. The fiancee has to apply for the sponsorship since they are her parents and you can co-sign so your income is counted too.
If they also qualify to be sponsored under the provincial nominee program, under age 49 etc., the uncle could sponsor them first (while they are still under age 49) and then they can wait until they qualify to sponsor you under the provincial nominee program, usually have to live for a year or two in the province because you can sponsor. That way they could be there first and you could be there 2-3 years later.
First check the website if you think that some or all of your qualify for the PNP and have the uncle call the PNP and find out.