If you need the money in the next 1-2 years, I would it in your savings account or GIC. If you only need a portion of that money (i.e, if you only need a smaller downpayment), then put the downpayment portion in a relatively liquid investment vehicle, and the rest in TFSA/RRSP/taxable account.
In terms of what instrument you invest in, that depends on your IPS (investment policy statement). For us, we just invest in equity index ETFs, like VCN or VUN, so that's where we would put any extra money.