Here are the links where you can suggest translations to those strings in Coraline:

"Continue reading"
"Posted on" and "by" (so that you can have the entire string; be sure to keep the encoding).

If you are new to GlotPress, here is how it works: http://en.support.wordpress.com/glotpress/

Note that the Greek translation project is not very active at the moment (it's 17% translated, and it might take a while until your translations are validated and go live), but Greek (Polytonic) is 79% translated and is updated often, so you might want to consider that option. You can change this option under Settings > General > Language ("el-po" stands for "Greek Polytonic").

I hope this helps, let me know if you have further questions!