Using MSACESS For Translations?

I will try and explain the scenario as best i can...

Ultimately, i will have 3 tables... one table with values and the other two that map to new values for the old table...

TABLE1:
Old_Value1
Old_Value2
Old_Value3 (Can be null)

TABLE2:
Old_Value1
Old_Value2
New_Value1
New_Value2

TABLE3:
Old_Value3
New_Value3
New_Value4

Based on each record in TABLE1.... the select statement should return
TABLE2.New_Value1, TABLE2.New_Value2, TABLE3.New_Value3, TABLE2.New_Value4

Ultimately, I am reading each record in Table1 to return the translated values from the other tables.

IMPORTANT: Sometimes TABLE1.Old_value3 can be null so the lookup is not necessary but I need the first lookup to occur...

So i need some IF logic and way to fetch values within the original select.. Here is the kicker... I can't use SQL Server... only what msacess provides and i don't know any VB....actually... if the value is NULL i can return "000"


p.s. I am an oracle guy... but they want this solution portable (MSACCESS) on a laptop with no connectivity... otherwise i would have written a package with store procedures..

Even if anyone could suggest a good HELP topic to lookup...