Question: Is there a way I can import my ReadItLater's exported html file into my Instapaper?

Answer: 
Though I don't have a tool now, I guess it can be done in couple of ways. Yes, no one click solution.

1. Email each url to your personal instapaper id ([Refer this Lifehacker article](http://lifehacker.com/5493449/instapaper-adds-email-functionality-for-easy-article-saving))
2. Can parse your export list and use simple API from Instapaper to add the links to your account. [Refer API docs](http://www.instapaper.com/api/simple)

**Update**:

As I said earlier, it is not a one click solution but doable. As a matter of fact, I did create an extension for chrome to do this. Here is the link <http://minus.com/mc3va2C>

**Update 2**:

The source of the extension is available @ <https://github.com/palaniraja/RIL2Insta>
No, there is no way of doing this. *With those applications.*