Hi,
Try asking a close friend if agency ( Tinies as mentioned are great, Sitters also good) fails, if they are really your friends they will not hesitate (you might be surprised)-I myself looked after 2 children for a friend over a long period of time in their house, who until today really appreciates it ( she was too scared to ask me until I overheard a conversation where I jumped in and offered my 'services', she thought I was ill
). That's what true friends are for!
Good luck!