Should I wait patiently if the professor asked me to wait for a few weeks? I am in my final year of PhD and submiting thesis in June. I had an interview for a Postdoc position about 2 months ago and gave an on site talk to the lab. The professor asked me to talk to each lab member individually to ask about lab culture, salary and so on. The professor and I then had  another interview and she briefly talked about the project I would be doing. When I asked about when I can know if I can get an offer, she asked me to await for like a month. She told me it's quite positive and very keen on taking me. But she has to think about grants and funding as she will be taking a couple of postdocs. After waiting for one month, she requested to wait for a few more months for her to be certain.
Only a few labs are available in the country I am applying for. So I don't want to apply for other labs and get rejected or rejecting their offer if any.
So should I just wait and see how she will reply before applying more? What is my chance of being accepted? Thanks!
she has to think about grants and funding as she will be taking a couple of postdocs. After waiting for one month, she requested to wait for a few more months for her to be certain.

This professor seemingly has no money to hire you. You should look elsewhere, whilst maintaining contact. If she gets money, it seems you are amongst those she'll consider hiring.