According to these reviews, there is no "answer book" for the text. There is a "workbook" associated with the text that does have an "answer key", but that costs extra and may deal with different questions.
Here are the links for that textbook. The Companion one (2nd) has some "Free Stuff" if you investigate:
Here are some of the sites I have for reference.
1. Tutorial = http://www.ielanguages.com/italian1.html
2. dictionary = http://www.freedict.com/onldict/ita.html
3. 3 beginning lessons = http://www.june29.com/Italian/
4. Learning Resources Online: http://www.iluss.it/
5. verbs = http://www.verbix.com/languages/italian.shtml
6. alphabet and pronunciation:
I hope you received the CD with your textbook.