SQL & PL/SQL :: Year To Date Value In Amount Field

I have a table and below are the rows:

create table employee_rev(employee_id number, month_name varchar2(10), month_end date, financial_year date, revenue_amt number)

Begin
insert into employee_rev values(111, 'DEC-09', '31-DEC-2009', '01-APR-2009', 1300);
insert into employee_rev values(111, 'JAN-10', '31-JAN-2010', '01-APR-2009', 1000);
insert into employee_rev values(111, 'FEB-10', '28-FEB-2010', '01-APR-2009', 800);
insert into employee_rev values(111, 'MAR-10', '31-MAR-2010', '01-APR-2009', 1000);
insert into employee_rev values(111, 'APR-10', '30-APR-2010', '01-APR-2010', 1000);
insert into employee_rev values(111, 'MAY-10', '31-MAY-2010', '01-APR-2010', 1100);
insert into employee_rev values(111, 'JUN-10', '30-JUN-2010', '01-APR-2010', 2100);
End;

I also need a YTD (Year to Date) field at the last which is sum of current month revenue_amt and sum(revenue_amt) for previous months for a particular financial_year_date.

The output should be:

Person_ID Month End Date Year Date Rev YTD
111 Dec-09 31-Dec-09 1-Apr-09 1300 1300
111 Jan-10 31-Jan-10 1-Apr-09 1000 2300
111 Feb-10 28-Feb-10 1-Apr-09 800 3100
111 Mar-10 31-Mar-10 1-Apr-09 1000 4100
111 Apr-10 30-Apr-10 1-Apr-10 1000 1000--change in financial year
111 May-10 31-May-10 1-Apr-10 1100 2100
111 Jun-10 30-Jun-10 1-Apr-10 2100 4200

I guess this should be achievable using some analytical functions, but I am unable to get the desired output.