Write some Software to compare prices from a set of numbers to three websites

What I want is a windows desktop based program. Basically the program will run numbers off an excel file. ISBN numbers of books. So it will take the first ISBN number in the excel file and it will search three websites, Amazon, Ebay and Bookscouter. What I want the program to do is do price compare against all three. So basically if it finds an ISBN number on ebay that is selling with a buy it now for 5.00 and it sells for 20.00 on amazon then I want to be alerted of this item. Or maybe that same ISBN number on ebay for 5.00 is only 4.00 on amazon but it's 18.00 on Bookscouter. Then I want to be alerted of that. Or maybe it's selling on amazon for .99 cents and it's getting 10 bucks on bookscouter. I'm trying to have the program find low prices on one site where they are a much higher percentage on the other. I need there to be filters such as only search books on bookscouter that is over 20.00 and if it isn't, that program will erase that isbn number and won't ever search it again. There is a few other filters needed just seeing if anyone thinks they can do this.