Try to get a ticket in Karnataka express. It's running as per schedule tomorrow. None available in tatkal quota in2s/sl/3ac. So keep looking for any opening on current reservation. This will be your best bet.
If not, you'll get lot of APSRTC/KSRTC buses from Puttaparthi, they pass near Station at a place called MM circle.
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more... If you don't find seats there, Station is some 10km away from bus stand and you'll get buses/autos to bus stand .
It'll be an extra effort for you, but you'll easily get buses to Bangalore.