Hey Dude,
New myself but ill try and help. In regards to getting in touch again, you have to remain consistent with how you previously convened, so if you aren't already sexual dont telegraph too much interest to begin with and aim for a meet up. Then you can make things more playful etc. If she is interested she'll be happy to hear from you so you can text pretty much anything to open and she'll reciprocate, 'Hey, long time no speak, been busy with (insert excuse), hows things anyway? x'. If she doesn't respond she's lost interest and it'll be near impossible to get it back without seeing each other.
I've done it a few times with random girls that i havent been in contact with and they all pretty much respond to anything casual. Once a conversation is going you can find threads to make it more playful/sexual without coming across too forward.
If i were you id just go meet other women, a few weeks is a long time
Just my two cents anyway, hope it helps.