Sadly 99% of the Runescape playerbase gravitates towards League of brown sticky stuffters because that game has an extremely low skill entry level (RS players are generally broccolied, so they go towards a broccolied game). Whereas DotA2 has an overwhelming entry level and an absurdly high skill requirement in order to have any semblance of "fun".
You should be specific about what sort of team you're looking for. what you can offer and what servers you can play on with mildly okay ping.
That said, I don't think anybody is going to take you seriously unless you're at least 5k mmr.