If you are in a valid H-1B status, your spouse (if/when you marry) is eligible for H-4 status (or a visa if abroad). As for the I-485, if you are seriously considering marriage, the sooner the better. Your spouse will only be able to adjust status with you if the marriage occurs prior to approval of your I-485. If you marry the day after the approval, you'll need to petition her in the F-2A classification and may be facing a several-year wait.
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There is nothing in your post that suggests she would be eligible for H4. You should talk to an immigration attorney and soon.
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