How To Separate Period Amount From YTD Amount

I'm creating a temporary table in a Sql 2005 stored procedure that contains the transaction amount entered in a period <= the period the user enters.
I can return that amount in my result set. But I also need to separate out by account the amounts just in the period = the period the user enters. There can be many entries or no entries in any period. I populate the temporary table this way:

SELECT
t.gl7accountsid,
a.accountnumber,
a.description,
a.category,
t.POSTDATE,
t.poststatus,
t.TRANSACTIONTYPE,
t.AMOUNT,
case
when t.transactiontype=2 then amount * (-1)
else amount
end as transamount,
t.ENCUMBRANCESTATUS,
t.gl7fiscalperiodsid

FROM
UrsinusCollege.dbo.gl7accounts a

join
ursinuscollege.dbo.gl7transactions t on
a.gl7accountsid=t.gl7accountsid

where
(t.gl7fiscalperiodsid >= 97
And
t.gl7fiscalperiodsid<=@FiscalPeriod_identifier)
And poststatus in (2,3)
and left(a.accountnumber,5) between '2-110' and '2-999'
And right(a.accountnumber,4) > 7149
And not(right(a.accountnumber,4)) in ('7171','7897')

order by a.accountnumber

Later I create a temporary table that contains budget information. I join these 2 temporary tables to produce my result set. But I don't know how to get the information for just one period. For example, if the user enters 99 as the FiscalPeriod_identifier, I need a separate field that contains only those amounts(if any) that were entered for each account in Period 99.

Can anyone help? It may be that I am not seeing the forest for the trees, but I can't figure it out.

Thanks very much.

Sue