Kobo says the $170 Aura HD e-reader now accounts for “up to 27%” of its device sales

When Kobo launched its “luxury” e-reader, the $169.99 Aura HD, last month, I was skeptical that anybody would shell out for it when cheaper models are available. Early sales results, however, suggest that I was wrong: Kobo announced Tuesday, a day before BookExpo America begins in New York, that the month-old Aura now accounts for “up to 27 percent of Kobo devices sold at retail, with more than 50 percent of those customers being new to Kobo.” The company didn’t reveal how many devices it has sold.

In addition, Kobo says its revenue grew by 98 percent in the first quarter of 2013, compared to this time last year. During the quarter , it says it “grew its user base by 2.5 million readers, bringing its total registered users to 14.5 million, with 15 percent of its new user base coming from the U.S.” That last point is important, as it suggests the Toronto-based Kobo is making some progress in cutting into a U.S. e-reader market dominated by Amazon (s AMZN) and, in a distant second place, Nook (s BKS).

Kobo’s been stressing for awhile that the e-reader market is alive and well: In January, the company said it doubled its e-reader sales in 2012. The company is also expanding rapidly. The Aura, currently available in the U.S., U.K., Canada, Italy and Germany, will launch in Australia, France, the Netherlands and Brazil “in coming months.” More broadly, Kobo plans to expand to India, China and Russia.

The company also revealed that ebooks released through its year-old self-publishing platform, Writing Life, now make up 10 percent of its revenue, “with 10 percent of the top 50 bestseller list comprised on independent authors.”