Roth IRA limits are currently $5,500 per year, and you can have one as well as a spouse (as long as one of you earned income over that amount). So yes, opening Roth IRAs for you and your spouse for 2015 - $5,500 each for a total of 11,000 per year.
I would suggest opening them at someplace like Vanguard and investing the total amount in VTSMX (this is the investor class for VTSAX, but only requires a $3,000 minimum investment). Then as soon as January comes, invest another $5,500 for 2016 for you both and ask Vanguard to roll it into the admiral shares (VTSAX).
Who has the 403b right now? Is this still being contributed to?
What is your mortgage interest rate? If it is above 5%, I'd look into a refi, but if you are unable to do that, I'd probably start making extra payments to knock it down sooner.
If it was me, I'd do this with the 40k:
11k out now to fund Roths for you and your husband;
then add in $11K into the existing Cap One savings both as a buffer since you've got one spouse not working full time and also to fund your 2016 Roths in January if you are able to add over the next 6 months, (but might check out Ally Bank or similar online banks that have savings rates around .99%);
and then the remainder into a taxable brokerage account and invest it (tax efficiently) into VTSAX as well.
Probably might want to check into funding kids' college accounts like 529s, but I know nothing about those personally.
But definitely hope some of the more savvy forum members chime in with (probably) better advice. :)