1. Giottos Rocket Blower (a simple air blower to help get rid of loose particles that may become attached to your camera body/sensor, lens etc.)
2. After blasting with a rocket blower, you may need a lint free microfibre cloth to clean your glass especially if you're shooting at the seaside (sea spray) - just search amazon or ebay for 'optic cloth' or something similar, or get one of these lens pens (never personally needed one...)
As echoed above, I'd advise you just go out and enjoy shooting and make the most out of that 18-70mm for now.
I suspect that after this period, the next items on your shopping list will be a second lens with a longer focal length, and probably a tripod
Enjoy