treat like a number

Gea

Hello, i want to order a colum which have numbers, but it's are ordering the numbers like Strings.
How can i treat the String like a number?
"
My example is ordering like that:
800.000
800,000
232,000
10.000.000,54
"
Also, i'm testing to exchange the "," to "."
if i have:
1,000--> one thousand
i want:
1.000--> one thousand
Thanks!

Gea

i did with sorting plugin :)
i will do a new question for the commas thing