Those were the 2 trickiest (US release) issues for me to find.
Seriously, it took months, I'd go buy
Futurama-o-rama or
Futurama Adventures instead to get the stories.
And if you're talking about the UK release of the comics, then issues #3 and #4 were the simpsons crossovers, which are also bloody awkward to find (I haven't got them yet) - you won't get them on a website, it's eBay or nothing I'm afraid.
I've seen them on eBay a few times but the prices are nasty, a friend of mine has the first 3 somewhere and is quite willing to part with them as soon as he finds them up amongst the crap in his cupboard. I'll probably get them when he moves house
.