Please read the first post in this thread for further information
As you are sponsoring your spouse, you are exempt from meeting minimum income requirements, you only need to show you are not in default of any previous sponsorship arrangements (not applicable to you) or an undischarged bankrupt. Your parents and siblings cannot co-sponsor your spouse so far as I know.
What you need to focus on is documenting your plans for resettlement. As a citizen sponsoring from outside Canada, this is important for you to show. So, the savings for the house (bank statements etc), any contacts you have established with regards to your house hunt, what arrangements you have made to stay with relatives (if any), any job searching you have undertaken should form part of your application. Having your relatives establish that they are aware of your plans and any support they are providing/will provide for you both will be great too.