Okay, so here's the thing. We're in a 1000 square foot 2 bedroom apartment. No garage, no yard. We both have moderately space intensive interests that require equipment. I cook a lot, and my husband has a piano and assorted equipment related to that. We have a 1 year old. About 200 square feet of our apartment is the living room, which basically serves to house the pull out couch my parents sleep on, park the strollers and little else.
If you want my opinion, I think you're jumping the gun. Your condo may not be the home you want when you have, say, a 6, 8 and 10 year old. If you delay having kids for 5 years, that scenario is, minimum, 15 YEARS away. Even once you have kids, for a lot of years, your kids are going to be small, and they are not going to require a lot of space. My daughter doesn't have her own room and, frankly, wouldn't take it if offered. We set up an adorable nursery in half our bedroom, and she doesn't require a lot of play space because, well, mostly she follows me around all day like an enthusiastic puppy.
You have a really inexpensive housing situation right now, and I think you'd serve yourself and your future family well by sticking it out for a few more years to save money. I'd make a thorough evaluation of your STUFF, and see what, if anything, you can purge. I am constantly pruning around here to keep our possessions down to something reasonable, and it helps a LOT. I also spent some money building out storage solutions that make sense for a small space. My dad and I IKEA hacked a nice pantry because the kitchen has bad storage, and I replaced all our end tables with tiny two-drawer dressers for added storage. It cost some money, but we have a good cheap housing situation, so it was worth the expense. Let me know if you want pictures of anything.
If I were you, I would suck it up in the condo for, say, 7 more years, and then move straight into the larger house.