ORDER BY question

Hope this is the correct forum - if not sorry.

I have a query which returns a value of the form: '20010822.1338.1'.

I would like to order the results, sorting :
    1st: 20010822    2nd: 1338    3rd: 1


I can do this in perl, but have not found a way to do this using ORDER BY.

I am VERY new to DB's; biologist trying to do informatics.

Thanks.
-- 
Chuck