string based custom ordering in active record

[eluser]tsandesh23[/eluser]
The category is a field in item table and (‘Auto & Accessories’, ‘Couch’, ‘Bed’, ‘Desk & Office’, ‘Bike & Scooter’, ‘Tools’, ‘Leisure’, ‘Iron & Wood’, ‘Cabinet’, ‘Kitchen & Accessories’, ‘Refrigerator & Appliances’, ‘Toys & Games’, ‘Chair’, ‘Table’, ‘Garden & Terrace’, ‘TV, HIFI & Computers’, ‘General Item’) are the possible values in category list. One record can contain one of above value and these are the only possible values in category field.
The problem is, the database is already designed and is live and thousands of customers are using this service. Initially, this project was built in normal php+mysql, but, our company need to change it into CI.

So, I can't change the database schema. Only thing that I should do is make the exact copy of previous code in CI and all the queries in active records. So, please help me to order these categories in above order.