PL/SQL :: Get Sum Average And Projected Totals In Same SQL

Version : 11g

I have a table with the following format and data

Serial no    exp_Date  exp_type   exp_amount
1              01-nov-2012   Rent       10000
2              02-nov-2012   gas          250
3              02-nov-2012   insurance   9500
.
.
.

I want to create a sql output for a yearly view in the format

   exp_type        JAN            FEB      MAR        APR ..... NOV  DEC          TOTAL     AVERAGE    PROJECTED
    Rent             10000        10000   10000     10000   10000  10000      120000     10000        120000
    gas                250             250     250        250      250      250          3000         250           3000
.
.

Now a couple of things in this

1. the average gives the average for the year, so lets say its start of 2013 and we are in feb, there will not be any values for the remaining months, so it should do the average for that exp_type for Jan and Feb based on the exp_amount entered against that type and show what is the expected average. Similary, projected will that average amount and mulitply it by 12 to show the exp amount expected based on current expenses

I was able to come up with the following sql to get the sum based on months, was not sure about average, total and projected

SELECT       exp_type
,        SUM (CASE WHEN to_char(exp_date,'Mon') =  'Jan' THEN exp_amt END)     AS Jan
,       SUM (CASE WHEN to_char(exp_date,'Mon') =  'Feb' THEN exp_amt END)     AS feb
,       SUM (CASE WHEN to_char(exp_date,'Mon') =  'Mar' THEN exp_amt END)     AS Mar
,       SUM (CASE WHEN to_char(exp_date,'Mon') =  'Apr' THEN exp_amt END)     AS Apr
,       SUM (CASE WHEN to_char(exp_date,'Mon') =  'May' THEN exp_amt END)     AS May


[Code]....

getting the correct avg, total and projected fields also in the same sql?