How i do accounting of an event?

Sure,

As per my opinion you must split as two financial year,

your event start from 01-03-2013 and end 15-04-2013, so total days = 45 days

If the incurred amount is Rs 1,00,000/- then please see my calculations

(100000x31)/45=68889 for current period

And 100000x14/45=31111 for prepaid expenses.

Then you are not mentioned the nature of this event, if it is for advertising then it comes advertisement expenses, and Prepaid advertisement expenses

If it is your business’s annual day celebration then its comes under business promotion,

Thank you