The HIB is a dual intent visa so you can apply for immediate relative petition at the time needed but if your marriage is strong and you have plenty if evidence and your answers were consistent then no need to file extension but is a good precaution. Once the GC is approved the HIB is void
Being married for one year means that you got your green card based on the marriage and that you are a conditional green card holder. The same form ( I -751) can be used to file for removal of the condition or for a waiver. A waiver means that you are filing for the permanent green card in 90 day window before its expiration based on the bona fides or good faith marriage on your own without the spouse.
This requires a showing that the marriage has been a viable one so you would need to...
DDo you mean they are revoking your US visa or that you are a citizen and they are revoking that? It seems that the first questions would be where do you live and what caused this letter response. There can be numerous reasons for the visa revocation so you should give alot more information and speak to an attorney.