If you're away for 7 days, I assume that you must be 'travelling light', since you can't use Ryanair's online check-in service if you've got hold baggage:
http://www.ryanair.com/site/EN/faqs.php?sect=c hk&quest=children
Further, online check-in is only available two days prior to travel, not five:
http://www.ryanair.com/site/EN/faqs.php?sect=c hk&quest=when
Ryanair's booking system doesn't recognise the concept of a 'return ticket'. It treats your outbound and return flights as two entirely separate bookings. Whenever I take a day trip (which means that I can check-in for both flights at the same time), I have to go through the whole procedure twice. (I can't check-in for two flights simultaneously). So, as far as Ryanair's computer is concerned, your return journey has nothing to do with your outbound trip and you'll need to find an internet caf� if you want to check-in online when you return.
Chris