The fee is $1040 in total unless you are in Quebec then add CSQ fee
The online application form is broken into 3 parts Part A for the Sponsor your fiancee:
http://www.cic.gc.ca/english/information/applications/fc.asp#sponsor•Document Checklist [IMM 5491]
•Application to Sponsor, Sponsorship Agreement and Undertaking [IMM 1344] PDF, 356 KB
•Sponsorship Evaluation [IMM 5481] PDF, 110 KB
•Statutory Declaration of Common-Law Union [IMM 5409] PDF, 97 KB
•Sponsor Questionnaire [IMM 5540] PDF, 160 KB
•Use of a Representative [IMM 5476] PDF, 55 KB
Part 2 for you the Permanent Resident Application:
http://www.cic.gc.ca/english/information/applications/fc.asp#sponsor•Generic Application Form for Canada [IMM 0008] PDF, 536 KB
•Additional Dependants/Declaration [IMM 0008DEP] PDF, 472 KB
•Schedule A – Background/Declaration [IMM 5669] PDF, 170 KB
•Additional Family Information [IMM 5406] PDF, 134 KB
•Sponsored Spouse/Partner Questionnaire [IMM 5490] PDF, 142 KB
•Use of a Representative [IMM 5476] PDF, 55 KB
and Part 3 Region Specific guide USA
http://www.cic.gc.ca/english/pdf/kits/guides/3910e.pdfgo through all those files and you will be pretty much done.
Since you are American you can come and go freely subjected to the CBSA discretion.