How do I Convert EBCDIC Character Overpunch Values to ASCII?

This is a difficult question worth 500 points to whom ever can provide a solution ASAP, as I need to have a working solution in place by 4/14/2008.

I have tried everything I know to convert an EBCDIC Character Overpuch Currency Value into ASCII format with a floating point leading sign value.

For example, the following is the original state of the value (the comma I have added to seperate fields as a precursor of an import into SQL):

0000894A,0000638N,0000103},0000345F,0000111{

I need to convert this into the following:

89.41,-63.85,-10.30,34.56,11.10

There are approximately 10k records per file with about 15 currency values one after the other. I have no dificulties in inserting the decimal, or dropping of the leading zero's, nor converting the graphic sign into its consituent numerical value, but cannot seem be able to insert the negative sign when needed at the beginning of the value, when I do insert through a simple find and replace command I have only managed to do so at the need of the value string, at which point the value is not treated as numeric or negative, but rather as a text string by Excel (where I need to do further manipulation before importing into SQL) and SQL.

 The full graphic sign table is as follows:
{ = 0
A = 1
B = 2
C = 3
D = 4
E = 5
F = 6
G = 7
H = 8
I = 9
} = -0
J = -1
K = -2
L = -3
M = -4
N = -5
O = -6
P = -7
Q = -8
R = -9

Any assistance would be greatly appreciated!

FYI: I am using UltraEdit v14, File is encoded DOS, from an original .DAT file sent to me from an outside source.