Look Back Through Records To Apply Funds Appropriately

I have a table holding transaction data: money owed / money paid. The vast majority link together, however, a small % do not. I need to apply money paid to money owed. I want to give the client the benefit of the doubt, while using some logic in the application of funds.

I know when the transactions occurred, so I decided to work from newest to oldest, applying available funds from any money paid that is newer than the money owed. When the process completes the look back for an account, there may be money paid left over. This is okay, as it could apply to money owed transactions prior to the look back period.

I have code in place to accomplish this. My problem is the amount of time the process takes to run. At the current pace, it will take well over a day to complete. Here is an example of what the data may look like for one account:

Code:
TranDate TranType Amount
01/05/2008Owed $50.00
01/24/2008Paid$75.00
04/15/2008 Owed $43.75
04/28/2008Paid $50.00
05/23/2008Owed$43.75
08/19/2008Owed $35.20
02/10/2009Paid$14.15
03/16/2009Paid $9.50
06/14/2009Owed $63.45
09/24/2009Paid$40.00

Here is what I want to accomplish:

Code:
OwedTranDateTtlOwed PaidTranDatePaidTranAmtPaidAmtAppliedPaidAmtRemainingOwedAmtRemaining
06/14/2009$63.4509/24/2009$40.00 $40.00$0.00$23.45
08/19/2008$35.2003/16/2009$9.50$9.50$0.00$25.70
08/19/2008$35.2002/10/2009$14.15$14.15$0.00$21.05
05/23/2008$43.75$43.75
04/15/2008$43.7504/28/2008$50.00$43.75$6.25$0.00
01/05/2008$50.0004/28/2008$6.25$6.25$0.00$43.75
01/05/2008$43.7501/24/2008$75.00$43.75$31.25$0.00

Here is the code to accomplish the look back:

Code:
DECLARE
@AcctNumDECIMAL(10,0),
@TranDateDECIMAL(8,0),
@TranSeqDECIMAL(4,0),
@TranODINT,
@TranTypeVARCHAR(20),
@TranAmtDECIMAL(7,2),

[Code] .....