Persistent decimal rounding

Hi.
My worksheet has a column full of numbers that are suffixed with "." and more numbers.

Example
Before After
135443.234 135443.23
456544.810 456544.81
435466.235 435466.24
654352.8 654352.80

I save my files as .txt. In the text files, the numbers appear preserved. But when they're opened in excel, they're rounded. If I format them as numbers with 3 decimals, the "#.8" becomes "#.800" which is no good. Oh, and the suffixes which end in a zero always end up losing the zero.

I've formatted my columns as general, number (with 3 decimals), and as text. That hasn't worked.
I've tried concatenating, separating the decimal from the suffix: =456544&"."&810
I've tried using the value formula to get get the cell value.

I don't know what to do now. Does anyone have a solution? Thanks.

All of my numbers are < 15 characters. That's good to know though, thanks.

Thanks Martin,

The import wizzard works for me.