There are two immigration issues here
Canada
You can sponsor your husband to join you in Canada as a member of the family class for Canadian Citizens or Canadian Permanent Residents. He would be granted an immigrant visa and would then 'land' in Canada from which date he would be a Can PR. If as it appears that you are a Canadian Citizen you can sponsor your husband whilst still in the US. Can PR's have to establish residence in Canada before they can sponsor in the family class. Your husband would have to undertake security and medical tests - note that he cannot be denied an immigrant visa on medical grounds.
Processing times at a Canadian Visa Post - in your case Buffallo, NY would typically take 6 months or less. During this time your husband would in theory be able to visit Canada but the discretion to allow his entry would rest with the Immigration Officer. If he had fairly strong ties in the US e.g. employment he may be able to get entry as a visitor.
If you wish to proceed with an inland processing your husband can again enter Canada as visitor but must tell the Immigration Officer that he intends to undergo sponsorship in Canada. The major disadvantages of inland sponsorship are:
1. Processing time of 12+ months - there are horror stories of it taking 18 months.
2. Your husband is not able to work until he receives an Approval In Principal - this may be quite tough on your financial situation.
3. Leaving Canada during the processing period will result in his application being abondoned.
4. The requirement to be in status throughout the processing period i.e. he has to keep renewing his visitors visa.
On the other hand this is balanced by the fact that you are together during this period.
Check out
www.cic.gc.ca for more info on this including the relevant costs.
US
You are currently undertaking an Adjustment of Status - I presume you entered the US as a visitor rather than a fiancee visa. Depending on your service centre the AOS may be as long as 2 years (Texas). If you leave the US before obtaining Advance Parole you will be deemed to have abondoned your AOS application. Perhaps as things stand you feel that the US is not for you - I would suggest applying for AP in any case to keep your application proceeding. If you then decide to return to the US you don't have to start from scratch. An alternative would be to abandon the adjustment application alltogether and apply for an immigrant visa as the spouse of a USC if you ever want to return to the US. Note that you may have difficulties entering the US as a visitor in future (which requires non immigrant intent) because you are the spouse of a USC although that the USC is residing with you outside the US is a plus.
Hope things work out for you.
