Are you already maxing your Roth?
Assuming you are, you wouldn't want to use that money. Also, for clarification, the Roth account does not need to be open for 5 years to take out contributions, only gain or money that has been rolled over from another retirement account.
Since you want it in 3-5 years, I'd stick it in the Capital One account.
Have you considered using equity in your house to finance the improvements?