Buy X Free Y Lowest in Magento

I was looking for a extension or added feature for magento which is able to do the function buy X free lowest Y in magento 1.3 or 1.4. Please get this if you are able to start work immediately and get this complete within 1 week time as it is urgent. It should be able to support below senario a) eg. I want to buy 4 free 1(lowest free). But I want it to be able to step further like if I buy 8 then it should free 2 (lowest free) in a single checkout. 2) if there is only 1 quantity for the lowest price, if I buy 8, 12 or above, will it be able to discount for second lowest since the 1 quantity lowest already been discounted on the first part. Features we needed are: 1) Eg. when we buy 5 then get the fifth item free (with lowest price), it should be able to multiple forward when customer purchase 10 will get fifth and tenth item free (means buy 10 get 2 cheapest item free) ,buy 15 get 3 free, buy 2- get 4 free and so on.... But when customer purchase 6, ,8 and 9 should only discount 1 quantity until they came to 10 will get 2 free. 2) Eg. When client purchase 1 item with 50 dollar (lowest) and 4 items 100 dollar. It match the condition buy 5 and should get the cheapest (50 dollar free). But come to case when customer purchase 1 item with 50 dollar (lowest) and 9 items 100 dollar, it match the condition and should give 2 free as he buy 10 in total. So the system should be able to justified only 1 product is purchased in cart and 1 item of 50 dollar (lowest) should be discount. Another discount item will be the second lowest, in this case is - discount 1 item of 100 dollar since it is the second lowest beside the 50 [login to view URL] should no discount 2 items from the lowest which is two of 50 dollar as the cart only have one 50 dollar(lowest) item. Second similar example, in cart there is 1 item of 50 dollar, 5 item of 80 dollar, 4 item of 200 dollar. Then similar 1 items 50 dollar( lowest) and 1 items 80dollar (second lowest) should be discounted. 3) All the lowest items for discount is based on per unit price and not the subtotal if the quantity is multiple. Even when the subtotal of the lowest item greater than 1 single higher value item, discount condition always apply to item with lower per unit price.