1.) Sorry not a big computer person
2.) Hmm well in English the word order is Subject, Verb, Object. In Japanese the word order is usually Subject, Object, Verb. Example:
English: Musoka reads a book.
=Musoka (subject) reads (verb) a book (object).
Japanese: ムソカが本を読む。(Musoka ga hon o yomu)
Musoka(subject)ga hon(object) o yomu(verb)
ga and o are particles, you will learn them pretty quickly, because almost all sentences have them.
すみません(Sumimasen) generally means 'Excuse me'
ごめんなさい(Gomen nasai) means 'I'm sorry' ごめん(gomen) is also commonly used.
3.) I am allergic to dust.
I'm not too sure about this one..But people might know what you mean if you just say
「私のアレルギーはほこりです。」
(watashi no arerugii wa hokori desu) (My allergy is dust)
How much does ______ cost?
Xはいくらですか。
(X wa ikura desu ka) (How much does X cost?)
Where can I find _____?
I haven't come across a Japanese equivalent of this..yet..But you could always say
Xはどこですか。
(X wa doko desu ka?) (Where is X?)
Do you speak english?
There are few ways to say this. But literally it would be:
英語が話せますか。(eigo ga hanasemasu ka) (Can you speak English?)
Or can use
英語がわかりますか。(eigo ga wakarimasu ka) (Do you understand English?)
I would guess that usually the person you're speaking to knows you're addressing them, but if they don't you can put あなたは(anata wa) in front of the sentence, so it would become:
あなたは英語が話せますか。(anata wa eigo ga hanasemasu ka) (Can you speak English?)
Or use the person's name instead of anata wa to make it more polite.
ムソカは日本語がわかりますか。(Musoka wa nihongo ga wakarimasu ka)
(Do you(Musoka) understand Japanese?)
Hope I've been of some help