Here's one set-up to try ..
Assume the sample data below is in sheet: Client Log
in B1:E8, data from row2 down
County Amt1 Amt2 Date
County1 419 381 01-Jan-04
County2 212 161 24-Jan-05
County1 339 331 02-Feb-05
County3 467 403 15-Feb-05
County3 499 204 23-Mar-05
County2 487 329 24-Mar-05
County1 123 131 25-Mar-05
etc
In an empty col to the right, say col G,
Put in G2: =IF(B2="","",IF(COUNTIF($B$2:B2,B2)>1,"",ROW()))
Copy G2 down to say G1000 to cover the max expected data range
in cols B to E (can copy down ahead of expected data input)
In sheet: Billing Details
---------------------
Put in A1

1 the 4 labels:
County, CurrMth, CurrYr, ToDate
Put:
in A2:
=IF(ISERROR(SMALL('Client Log'!$G:$G,ROWS($A$1:A1))),"",INDEX('Client
Log'!B:B,MATCH(SMALL('Client Log'!$G:$G,ROWS($A$1:A1)),'Client
Log'!$G:$G,0)))
in B2:
=IF(A2="","",SUMPRODUCT(('Client Log'!$B$2:$B$1000=A2)*(MONTH('Client
Log'!$E$2:$E$1000)=MONTH(TODAY())),('Client Log'!$C$2:$C$1000)+'Client
Log'!$D$2:$D$1000))
in C2:
=IF(A2="","",SUMPRODUCT(('Client Log'!$B$2:$B$1000=A2)*(YEAR('Client
Log'!$E$2:$E$1000)=YEAR(TODAY())),('Client Log'!$C$2:$C$1000)+'Client
Log'!$D$2:$D$1000))
in D2:
=IF(A2="","",SUMIF('Client Log'!B:B,A2,'Client Log'!C:C)+SUMIF('Client
Log'!B:B,A2,'Client Log'!D

))
Select A2

2, fill down to D1000
(cover the same range as in sheet: Client Log)
The above should return what you're after:
Col A will produce a list of the unique counties in Client Log
Col B will return the sum of the amounts from the 2 cols: Amt1 & Amt2 in
Client Log for the current month by county
Col C will return the sum of the amounts from the 2 cols: Amt1 & Amt2 in
Client Log for the current year by county
Col D will return the sum of the amounts from the 2 cols: Amt1 & Amt2 in
Client Log for "life to-date" by county, i.e. irrespective of the date
entered
For the sample data in Client Log,
you'll get in Billing Details:
County CurrMth CurrYr ToDate
County1 254 924 1724
County2 816 1189 1189
County3 703 1573 1573
(rest are blank [""] rows)