It's a completed action and you specified the time so I'd probably go with 'took'. I mean if you had literally just walked in the door and you didn't specify the time, I might use 'has taken'. As for walking the dog I would say 'to take my dog out', or 'to take my dog for a walk' or 'to walk my dog' (to avoid repetition of 'take' maybe the last of these would be best) rather than 'walk my dog out' which doesn't really work. I'd also say 'the dog' rather than 'my dog'.