I am a software engineer working from home, and need a backup internet connection (for when Telstra stops working). I just bought a Vodafone vodem stick for 80$, but the rates are just terrible in my house, on Kelburn/Highbury in Wellington:

I didn't know that 3G could be so slow indeed, especially 5min drive from the city center...
It sometimes doesn't find the 3G network at all, but most often connects with 1 bar out of 5.
I think there is nothing I can do to improve this speed... or is it maybe?
Would anyone maybe know a reasonnably cheap backup internet connection solution, that would provide maybe 1MB/s download rate? Since I am already paying for Telstra, I would be very happy to pay 10$ or 20$ (with limited data) to access fast internet when necessary.
Thank you for your help,
Matt