You can transfer basic information, like username, e-mail, birthday, sex using CSV import plugins. 

choose ow_base_question-data table and ow_base_user table in your Skadate database and export them in CSV format. 

Then on your Oxwall website you need to install this plugin http://www.oxwall.org/store/item/718

and import the CSV file you have exported with 2 tables.