So many students and people in general tell us, that their "grammar is bad" or they don't have enough "vocabulary" to speak English. If you wait until both your grammar and your vocabulary are good enough to communicate, your whole life will pass you by. Use what you have now and try to communicate! English is a Communication Tool, so use it and COMMUNICATE!
Most of the non-Japanese living here in Japan, know your English is not perfect, but neither is their Japanese. So why not try and communicate the best way you can?