Case in select after sum?

I'm trying to assign a different column to a sum depending on the dates. Here's what I have:

SELECT SUM(amount) CASE WHEN date BETWEEN '1/1/13' AND '1/1/14' THEN Last_yr_tot 
        WHEN date BETWEEN '1/1/14' AND 'now' THEN YTD

My entire query.

select  fd.location_cd
    ,round(sum(case when fd.fs_dt between '1/1/13' and '12/31/13' then amount else 0 end)::numeric, 0) as Last_yr
    ,round(sum(case when fd.fs_dt between '1/1/14' and current_date then amount else 0 end)::numeric, 0) as YTD
    ,round(sum(case when date_part('month', fd.fs_dt) = 1 then amount end)::numeric, 0) January_data
    ,round(sum(case when date_part('month', fd.fs_dt) = 2 then amount end)::numeric, 0) February_data
    ,round(sum(case when date_part('month', fd.fs_dt) = 3 then amount end)::numeric, 0) March_data
    ,round(sum(case when date_part('month', fd.fs_dt) = 4 then amount end)::numeric, 0) April_data
    ,round(sum(case when date_part('month', fd.fs_dt) = 5 then amount end)::numeric, 0) May_data
    ,round(sum(case when date_part('month', fd.fs_dt) = 6 then amount end)::numeric, 0) June_data
    ,round(sum(case when date_part('month', fd.fs_dt) = 7 then amount end)::numeric, 0) July_data
    ,round(sum(case when date_part('month', fd.fs_dt) = 8 then amount end)::numeric, 0) August_data
    ,round(sum(case when date_part('month', fd.fs_dt) = 9 then amount end)::numeric, 0) September_data
    ,round(sum(case when date_part('month', fd.fs_dt) = 10 then amount end)::numeric, 0) October_data
    ,round(sum(case when date_part('month', fd.fs_dt) = 11 then amount end)::numeric, 0) November_data
    ,round(sum(case when date_part('month', fd.fs_dt) = 12 then amount end)::numeric, 0) December_data

from financial_acct fa
    join financial_data fd
    on fd.acct_no = fa.acct_no

inner join (select sum(fd.amount)
    from financial_data fd
    where fd.fs_dt between '1/1/13' and '1/1/14'
    ) Last_yr
    on fa.acct_no = fd.acct_no

where fa.acct_no = '799-' and fd.fs_dt between '1/1/14' and 'now' 
group by fd.location_cd
    ,fd.fs_dt
order by fd.location_cd

It was requested that I put my entire query into the post. I will comply, but it needs more details. acct_no is account number. fs_dt is the date. location_cd is where the code is going.

You need to split these out into two columns. Each looking at the date range and returning the amount value or zero

select
  sum(case when datecolumn between '1/1/13' and '1/1/14' then amount else 0 end) as last_yr_tot,
  sum(case when datecolumn between '1/1/14' and current_date then amount else 0 end) as ytd
from
  myTable

Check this fiddle

Note that datecolumn and myTable must be replaced by your own date column and table names. As date is a reserved word in postgresql, it doesnt look much like a column name.