Alslamu Alikum, I started learning Urdu couple of months ago. I have a book called " the complete Urdu" by David Matthews And Mohammed Ka, Sim Dalvi, it is really good one . I also tried pimsleur https://www.pimsleurdigital.com/ audio , that one is really good if you want to be able to learn common phrases and be comfortable with the pronunciation, I love their teaching method. It is a big advantage that you speak Arabic because you will not have problem in reading (the script is a little bit different but it will not take you long to learn it )there is also a lot of common words between Arabic and Urdu. even the way we form a sentence is similar.. but I think the time that takes you to learn a language will depends on how much effort you put in to it . I hop that will help you. good luck :)