String Data Validation - SQL 2000

I need some suggestions on validating a string of text based on some business rules using T-SQL. I have a string similar to the following:

This is some text (1.00); this is some more (there's more text here) text (2.00); this is yet more text (1.10)

The above example illustrates a valid string. You'll notice the multiple sets of parens The parens that contain numbers must be followed by a semi-colon except for the last set of parens. Furthermore, any parens followed by a semi-colon must contain only numbers and not text. I can easily identify the positions in the string by using PATINDEX.

Get the closing paren not followed by a semi-colon, ignoring the last closing paren PATINDEX('%)[^;]', @string)
Get the closing paren followed by a semi-colon, ignoring the last closing paren PATINDEX('%);%', @string)

My question is, is there a way to quickly validate the data between the parens without visiting each character. This is SQL 2000 so using CLR regular expressions is out.

Thanks.