Help: what can i do?

I'm in a bad situation: I just joined a comany. I was interviewed
and hired by one manager, but for some reason the manager changed
(the current manager is an Indian.) I'm a Java guy and don't have
any VB experience(I mentioned that in my Resume). Even though I
worked very hard, I could not handle the client side (VB module)
well. Now I am catching up, but it's late. the new manager said i
could not reach his expectation. Yesterday, HR told me I will have
one month to look for other position interally. According to the
offer letter, within 3 months, the company can let me go without
penalty. It will be 3 months in less than one week. But i will have
to leave(i don't think i can find a new position in one month).
How can I do? I really need your advice