How to combine my data into one?

I am using piwik for my wordpress website. After updating to the Wordpress 4.0 and revising the name of the website last week, I realised that I don’t see any data recorded before my updates. Then, I go to my piwik interface (http://www.mydomain.com/piwik) and find out that Piwik automatically create another “Website” with my new website name under “Manage” on my account. Also, the new piwik data is combined with my wordpress database now. When I setup the database for piwik, I used a separate database, so it won’t be shared with wordpress database. Now, my previous data are recorded in the Website #1 (the original one), but the data after the changes are recorded to the Website #2.

Is there anyway it can fix? Or how can I combine my previous piwik database with the current database? Thank you!

hello please upgrade to PIwik 2.7.0 beta where this bug was fixed: Index of /