extension of visa urgent attention needed please guide me..

[av_gayatri]

My students visa is expiring on 30th Nov 2009 and as I have failed in my finance papaer my re-sit examination for finance is on 13th october 2009. My results are expected 6 weeks after my exam and in the mean time i am running short of my visa. I asked my college about this issue , but they said that they would request that the results should be out by 25th nov 09.
Am I eligible for the extension of student visa? and if yes, what period extension can I get? Also that, What amount of money do I need to show in my bank account for what period of time ? , as I have completed my course in oxford. For how much time can the home office give me extension .
If I pass the examination then its fine , but if I fail then the next resit will be in the month of dec- jan .
I am a bit confused because if they give me extension for results awaiting then that extension will be only for a period of one month, then I have to pay £400 as an extension fee, which is a huge amount for a months time .
Please suggest me for that...
thanks.

[koru cowboy]

I think your best option is to apply for extension on the basis of starting a new course and if asked for, indicate on the application that you are waiting for exam results of your previous course.That is the only way of getting a reasonable extension.