First a few words on how the reopening mechanism works. You can read more in the relevant Help Center article: What if I disagree with the closure of a question? How can I reopen it?
A closed question can be reopened either by the community or by a moderator. For a question to be reopened by the community, it needs to get 5 reopen votes. However, moderators can reopen any closed question single-handedly, without requiring the 5 votes.
There are two ways that the reopening process can be initiated for a closed question:
Either the OP (you in this case) or a user edits the question and checks the Submit for review option:
Either the OP or a user clicks the Reopen button right below the question, if they have the required reputation (3000 reputation points):
The screenshot above is from your own question.
Both of the above ways lead to the question sent to a special queue, the Reopen votes queue. There the community votes to either reopen the question or leave it closed:
As you can see, your question currently has received 2 Reopen and 2 Leave Closed votes in the Reopen votes queue.
Now, addressing your questions:
- How many votes do I have to get so my answer would be reopened?
You need 5 reopen votes, as I described above. These votes should not be confused with upvotes or downvotes that a question has. As you can see in the screenshot of your question I shared above, your question had 3 reopen votes at the time the screenshot was taken.
- Are there any other ways to reopen questions?
The two ways to reopen questions are described above. Additionally, if you have tried to reopen your question but it hasn't been reopened and you strongly believe that it should have, you can ask here or let us know in one of the two main chatrooms of the site: Raiders of the Lost Downboat, a room specifically used for moderation purposes (such as voting to reopen or close questions, flagging, etc.) or Ask Ubuntu General Room, a general-purpose room.
- Are there any ways I can bring more attention to a question other than bounties?
You cannot add a bounty to a closed question, so adding a bounty is not really an option for your current case. What can, however, increase the chances of your question getting reopened is to edit it and explain clearly why you disagree with the closing reason, in this case with the question that your question is closed as a duplicate of. This way the reviewers will know that you have, for example, tried the suggestions in that question and that they haven't worked for you.