The type of fostering that PetRescue rescue groups generally undertake is fostering of already homeless pets, with the view to adopting them permanently into a new family. Whilst many groups would love to help out, they may not have the resources to do so given the number of pets at immediate risk of being killed in pounds or shelters.
The PetRescue Rescue Directory will allow you to search through a list of all rescue group members, and sort by state to narrow your search. You can use this tool to contact groups in your area and see if they can help.
Another option may be to find pet boarding accommodation or a private pet-sitter until circumstances change.