السلام عليكم ورحمة الله وبركاته حياك الله وبياك شيخنا If our Arabic is not good enough, can we lift our hands in dua and ask Allah for forgiveness after finishing praying salah at tawbah?

I do not know of anything reported about raising your hands, but what I know is that you pray, you repent to Allah, you ask for forgiveness, and you make istighfar. As Imam Ibn Baz mentioned.