I'm pretty sure that it's too early to safely put a 1-year old in a bed by himself outside of a crib. He'll probably be able to climb right over that rail, and can fall and hit his head. And even if he climbs out in some safer way that you teach him, during the daytime, a groggy baby in the middle of the night is a different mattter.
I don't pretend to know the facts on this, but if it were me, I'd want to consult the experts. There's just too much at stake with a little one who wants to explore when you least expect it...like early in the morning or in the middle of the night. Having a new baby in the house will only exacerbate this. Then there's the problem of him exploring his room or the house unsupervised. There's only so much that babyproofing can do. As they say, there is no substitute for parental supervision. Especially when they're *this* young.
You can get a crib for SO cheap at a thrift shop or through baby showers. Or, you can do what most families do around the world: let your new baby sleep with you, and keep your son in his crib. Since he's used to sleeping on his own, it might cause more disruption to have him in bed with you, but if you start the baby off in your bed from day one, s/he will get used to being there from the start without learning to have enough room to kick and roll around and keep you awake.
Sleep sharing is at least as safe as the safest crib. Many researchers and pediatricians have concluded that it's safer, because the mother acts as a respiratory and heart "pacemaker" for the newborn, who is still learning to breathe through the night. So, it reduces SIDS. Some statistics seem to say otherwise, but those are from surveying parents of children who died in "alternative" sleep arrangements: on the couch, in the laundry basket (!), or in bed with parents who had been drinking, or Mom was still dopey from labor pain meds, or the parents did it ad hoc and didn't do it safely (pulling the blankets up, for example), etc.
But done properly, sleep sharing is extremely safe and helps the whole family to sleep much better. If you plan on nursing, it makes nursing/overnight feeding fantastically easy and convenient. You barely wake up while your baby latches on and nurses back to sleep when sufficiently fed.
It will also last as long as you like, whereas a bassinet only lasts till about 3 months of age or till the baby can roll over; whichever comes first. So, you can keep your newborn in your bed with you till your son is old enough to be in a toddler bed or similar situation. Just please read up on the recommendations for this so you make sure to avoid any dangers that you might not be thinking of off the bat.
You can learn more about sleep sharing at www.askdrsears.com.
Good luck with everything! And congratulations.
L.