Alter Column nvarchar to Money

I have a table that I get and I want to change an nvarchar(50) value to Money.
My column looks like:
0000500.00
0005190.00
0000100.00
I want to convert to Money but I get, Disallowed implicit conversion from data type nvarchar to data type money.
I know I can right click on the table and change this, but how can I do it in an Alter Column Stmt? If I try to do an Update or Convert before the Alter I get the opposet error...
Disallowed implicit conversion from data type money to data type nvarchar
I know this is probably easy, but I can't seem to get it done without right clicking on the table and selecting money.... then it's no problem!
Thanks In advance, jb