Wild Defiance and more targeting spells. Apostle's Blessing and definitely 4 mutagenic growths. Apostle's Blessing is great v creature decks AND control decks.I'd also cut cards for 4 gitaxian probes. makes the deck more consistent (basically a 56 card deck) and lets you make the best play every time.
Gut Shot is also awesome with defiance. it becomes a pump spell with defiance out, and it kills birds/delvers. its so unbelievably good.
this is what i would play;
4 Glistener Elf
4 Flensermite
4 Ichorclaw Myr
4 Plague Stinger
2 Gut Shot
4 Mutagenic Growth
2 Titanic Growth
3 Apostle's Blessing
4 Gitaxian Probe
4 Wild Defiance
3 Rancor
7 Forest
4 Inkmoth Nexus
7 Swamp
4 Woodland Cemetery
Edit: also, the best infect decks have been Blue/Green (with ponders and Blighted Agents) - it's 4-0'ed a bunch of daily tournaments on MTGO, and Green/White with Ajani, which has 3-1'ed a bunch of dailies too, for those checking. Mono-Green is horrible compared to either of those.
[Edited 2 times, lastly by dfitzg88 on August 27, 2012]