The IRS allows you to choose and file Injured Spouse with the amendment or by itself, after you have already filed.
Since you have to amend your tax return to add W2, you may file Injured Spouse with the amendment. Yes, you may be able to get refunded your portion of the original refund when you file Injured Spouse, but not before. Plase note that it may take 14 weeks for the Injured Spouse claim to be processed.
Please refer to the link below for amending instructions:
https://ttlc.intuit.com/replies/3288565