I don't know what is that "RTK1" you said, but I check on internet and maybe is a book of memorizing kanjis, isn't it?
I don' know how long would it take to learn those kanjis, but I am correct if I say that depends on you and your studying method and how much time you use for that.
I went to Japan to learn japanese. I studied in a japanese language school, so probably the method is different. But I'm sure you will have no problem if you take as much time as you can with the kanji, because they are really important (mostly to read and survive there).
I can tell you that I was using the book "Minna no nihongo" for grammar and for kanji. Every day we had a kanji test with 10 kanjis. With Minna no Nihongo you start learning basic kanjis that you will find again "inside" future complicated kanjis, so it is very difficult to forget them! And knowing the first kanjis you will be able to presume the meaning of the new kanjis thanks to that.
I would recommend that book. And there are also book with drawings that help a lot in memorizing the meaning (maybe RTK is one of them, I don't know, but there are a lot).
Sorry if I wasn't helpfull for your questions, but just don't be worried about how much time took your friend (or whoever told you that) in learning all those kanjis. It also depends on the person, it is easier for some people. But you don't have to worry, with time and A LOT OF PRACTICE you will learn fast without noticing. Just buy a lot of notebook and pens and practice!
P.D: Knowing kanji will help with your speaking skills, because the have a lot of words with same sound but different meaning/kanji. Vocabulary is always key for improving speaking.
And I forgot to say that when I started studying japanese with Minna no Nihongo I didn't know anything about japanese language, just Hiragana and Katakana, Hello, Goodbye and Thanks.