Don't worry - it's much easier with a toddler and a baby than where you're at now!!!
I would recommend gearing your day towards the toddler and then baby can just be dragged along when he/she arrives.
Have a little think about the types of things he seems to enjoy...e.g. 'hiding', sweeping, messy play, books, cars etc etc etc - literally scribble a list of one word ideas on a piece of paper and tape it firmly to a kitchen cupboard for an easy reminder.
You definitely need to leave the house at least once and preferably twice a day. Every day, go to either the park or local library and then meet up with a friend at theirs or yours / out somewhere daily if poss too. It's a difficult age as they don't seem to want to do anything for very long do they?? We usually stay in for half an hour or so after breakfast then go out and then pop out again 45 mins after waking from naps..
I would definitely leave the house by 9:30 and earlier if he seems to get tetchy before then. Make him walk as much as you can alongside the buggy as it will take longer and be an activity in itself and also be good exercise.
Brainstorming thoughts:
Park - swings etc or take a small bag and collect rocks, sticks and leaves, give him a dolls buggy to push around, kick a ball
Swimming (I can never be bothered with that myself)
Local library - often have toys in aswell as books!
Any playgroup you can get your hands on for 3 weeks and then just go to the ones you like.
Supermarket - they love sitting in the trolley but DO give him something to eat / hold
'Washing up' - standing at the sink on a chair / in the bath
Playdough
Plastic bowls and dried pasta / lentils and a couple of spoons
A bag with things that can be put in it and taken out again
Cars & trains
Helping with a household chore
Baking
Hiding - them or 'things! - big sheet draped over a couple of chairs / screwed up tissue in an upturned pot or stacking cup.
Must dash - more later!