How can i encrypt my already created columns in sql sever 2008?

Question

I have simply created my table

create table LoginInfo 
(
UserName Varchar(100)constraint user_primary Primary key,
Password Varchar(100),  
Rolleame Varchar(100),  
EmailID Varchar(100)constraint email_unique Unique,
SecurityQuestion Varchar(1000),
SecurityAnswer Varchar(100),
LastLogin datetime
)

i want to encrypt it by rsa algorithm. Please tell me how can i encrypt UserName, Password, and security answer.