Have a look at what H20Fidelity referred to and what the write ups about them are. I'm not sure how much benefit you'll gain with spending approx 100 on a pair of IEMs. They will be decent for sure, but whether the difference will be night and day will be another thing altogether. It's hard to make the call because we all hear things differently too.
I would go for any USB dac unit that improves on your laptop. But also, in my opinion, if one upgrades, they should take a few strides forward and not little by little. Another option is really to think about getting a DAP i.e. iPod or a dedicated audio player so to speak. That way, you use it when you move around etc. And they don't cost a crazy amount either. Then spend the rest on a good pair of IEMs. Heck, you may not even blow your whole budget out of the water.
And of the options in your two, I too would go the way of the TF10, though I'm not sure how much an amp would help if you are just using it from your laptop i.e. that's my caveat.