Just reading this it sounds as if you are saying you have a product which converts well at the price points $27 and $37 and you're worried this is too low to attract affiliates? go ahead and correct me if I'm wrong!
It would help if we knew what the software actually does? Is it a traffic package or something else wp plugin??
You've got a few choices here..
Have you thought about building on the fulfillment and providing more value to your product? if you do that you'll likely find that you can increase the price point somewhat although $37-$49 is a pretty good starting value for a basic buyer, so by adding training or additional software, any further relevant content that could help you close a sale, pitched effectively will help you boost those epcs.
Secondly you could go back and check the copy, test it, make sure it converts and that you're affiliates are going to see nice earnings from a promo for ya!
Lastly (and you should be doing this already) - get some top upsells in the funnel, following your $37 buyer, upsells will usually make the process of achieving whatever was promised in the initial sale easier for your buyer. I.e automating sections of it or by providing a benefit that is going to make success using your product easier to achieve!
Doing 1 or all of these things will help you get higher earnings from your product and in turn attract more affiliates to promote!