Group By Different Criteria

I have a table in the following format

reporting_date interest_payment balance
200401 10 10
200402 20 15
200403 30 20
200404 40 30
200405 50 40
200406 60 50
200407 70 60

i wanted to generate an OUTPUT in the following format :

The output of the query should look like this :

reporting_date interest_payment balance
Q1 -2004 60 10
Q2 -2004 170 30
Q3 -2004 70 60
Q4 -2004 0 0

i.e i wanted to represent data by quarter and year and group by quarter and year for interest_payment column but for balance i need to pick up the value from the first reporting date in that quarter ,so as you can see q1-2004 has 10,15 and 20 but only 10 is accounted as that was the first reporting date in that quarter

I have my query working for interest payment but i am not sure how do i pickup the first reporting value for balance in a quarter

SELECT report_year as "@date",'Q'+CAST(report_quarter+1 as varchar(1)) as "@quarter", SUM(a.balance) as "@balance", SUM(a.interest_payment) as "@interest_payment"
FROM (SELECT *,
(reporting_date%100 - 1)/3 as report_quarter,
reporting_date/100 as report_year
FROM employee) a
GROUP by report_year, report_quarter
order by report_year, report_quarter