Is it possible to get more than just 3 video and audio tracks in hitfilm 4 express
Yes, perhaps your timeline is a bit too small so that you don't see them.
To add more layers, simply drag a new clip above the existing clip (layer).
You can also right click and insert more layers like so:
Same thing goes for audio. It's even going to add 1x audio track and 1x video track if your clip consists of both audio and video.
You can have as many tracks in the NLE as you want. There is more than one way to create a track.
You can right click the track title header and choose to create a new track from there. You can drag media to an empty spot on the timeline. Top of video or bottom of audio. A new track will be created. For this you might need to scroll and/or resize the track panel to get that empty space.
Right clicked worked for me thanks