I wouldn't necessarily expect this weight gain to prevent you from conceiving if you haven't had trouble before. Some people have to lose (or gain) weight in order to conceive, but many overweight mamas (like me) were able to conceive at higher weights (mine is actually quite a bit higher than yours). It's very individual, and I think depends on the whole picture of personal health you have going on. I would focus on eating a healthy diet and staying active while TTC. If your age is a concern, then starting sooner rather than later is probably a good idea.
M/C at 8 weeks -- May 2000. DS #1 -- March 2001. DS #2 -- November 2002. (Ten year break!) DD -- October 2011. M/C at 8 weeks -- May 2013. Expecting #4 late July.