Funny you should say that - as that was exactly what I was going to suggest - especially as I think it highly likely that your bulb will very probably have a few bulblets already - however - although October is a good time to plant Hippeastrum bulbs - if the one you have in a pot is currently showing any signs of grow - then I would suggest that you wait until its finished its growth cycle and stopped blooming before you transplant it into your garden - which will most likely be early spring - as they do best when planted during their resting period
It doesn't have any blooms though. Maybe I can replant it next week. I can't do it this weekend because there is a typhoon here. :O It's very muddy in the garden!