Secure existing asp Web Applications

It's a game portal develop by my friend, Running fine under Windows XP,MS SQL 2000 Personal,Non-english windows [login to view URL] i want to secure the whole asp. -Add functions to generate a Hash and Salt value for ALL members Login/Admin password -Secure the whole section during SSL -Encrypt SQL connection String,Edit code to protect from SQL injection -Add functions to accept e-gold payment and credit the user account after payment. -Other suggestion welcome