Whether you can appeal a guilty plea will depend on your claim or your grounds for appeal. There are very few proper grounds for appeal after you have pleaded guilty. A proper ground would be if what you admitted to was not actually a crime or if the court did not have jurisdiction over you.
It looks like your wife wants to recant (take back what she previously said). It's not really a proper ground for appeal after a guilty plea, because whether she acknowledges the crime or not, you have. (It's not even a good reason after a trial. And it's especially unpersuasive in a domestic violence matter, where true victims go back and forth all the time, because of the nature of the domestically violent relationship.) If your wife says that she lied to police or the court to get you convicted, she could be charged with perjury. If convicted, her jail term would depend on her criminal history. A conviction for perjury would affect her credibility in every subsequent legal matter, whether she was a witness to a later crime or testifying on behalf of her children. So she could get into trouble and it would still not help you appeal your conviction. Also, if there is a no contact order as part of your sentence, which is common, your violation of this order by communicating with your wife could get you in bigger trouble.
There may be other grounds for appeal. One common claim is that the guilty plea was involuntarily made. But I do not think your facts establish an involuntary plea. You weighed the pros and cons and voluntarily decided to accept the plea bargain.
The first person you should consult about an appeal is the attorney who represented you before. If that person is too expensive, try a public defender in your area. If either of these do not have ideas, ask them for a referral to someone who does public appeals. Someone who specializes in this area may have some unique ideas.
While you are at it, ask your attorney how you would go about vacating a conviction after enough time has passed. Often times, a criminal conviction can be erased from the books after you have completed the probation time and paid your fines. If this is the only history you have, you should look into it.
The first question you need to answer is whether you still have time to file an appeal. There are deadlines. I believe Oregon's time to file a notice of appeal is shorter than most states. In my state, CA, it is 60 days from judgment.
No. In Oregon, you have 30 days from the date of entry of judgment to file a notice of appeal. You missed the deadline but don't kick yourself for it, as it likely wouldn't have been successful. Since you pleaded guilty, you could only have challenged the sentence anyway.
MARK YOUR CALENDAR for 8-13-2012. If you successfully complete probation by then, you can have it expunged if your record is otherwise clear. If not, wait 10 years.