No luck with Clomid - what's next?

I have been TTC for 2 years. Got pregnant 6 months ago w/ 50MG Clomid and timed intercourse. Unfortunately I miscarried 6 weeks later. After that, I had two unsuccessful <a href="">IUI</a>'s - one w/ 50MG Clomid and the other w/ 100MG + Medrol. My cycles are between 30-32 days and I tend ovulate quite late. What can I do to up my chances with the next <a href="">IUI</a>? Or should I just go straight to <a href="">IVF</a>?