We filed our 2017 return and recieved a 1099B a week after , what should we do?

You will need to add the 1099-B to your return. Since you have already filed you will need to wait until the IRS either rejects or accepts your return. In the meanwhile, do not go in and make any changes to your return.  

• If your return is rejected, you will be able to go into your account and make the necessary changes and re-submit your return.  
• If the IRS accepts your return, you must wait until it has been fully processed and you receive your refund or have paid your balance due to amend. You will need to prepare an amended tax return on a 1040X and mail it in if the new info changes your refund or tax due amount. You cannot e-file an amended return.  They have to be mailed, and it takes up to 16 weeks for the IRS to process an amended return. 3 weeks after you mailed your amendment, you can start tracking its progress at the IRS Where's My Amended Return? site.  

Amendment instructions can be found here:  https://ttlc.intuit.com/replies/6602208