ORDER/SORT Column mixed number and number prefixed by char

Question

I have a varchar column conteining a code, this code could by only numbers, or number prefixed by a char for example i have a column containing this data :

Answer 1

 CASE
    WHEN ISNUMERIC(Col) = 1 THEN '@'
    Else LEFT(Col, 1)
 END
,CASE
    WHEN ISNUMERIC(Col) = 1 THEN Convert(int, Col)
    Else Convert(int, RIGHT(Col, LEN(Col) - 1))
 END